九州大学 研究者情報
論文一覧
大嶋 孝志(おおしま たかし) データ更新日:2019.09.11

教授 /  薬学研究院 創薬科学部門 生命薬学


原著論文
1. Matsumoto Yohei, Taro Tsuji, Nakatake Daiki, Ryo Yazaki, Takashi Ohshima, Thionoesters as 1,2-Dipolarophiles for [4+2] Cycloaddition with Cyclobutanones, Asian J. Org. Chem. accepted., DOI: 10.1002/ajoc.201900156, 2019.04.
2. Megumi Noshita, Yuhei Shimizu, Hiroyuki Morimoto, Shuji Akai, Yoshitaka Hamashima, Noriyuki Ohneda, Hiromichi Odajima, Takashi Ohshima, Ammonium Salt-Accelerated Hydrazinolysis of Unactivated Amides: Mechanistic Investigation and Application to a Microwave Flow Process., Org. Process Res. Dev. 2019, 23 (4), 588–594, DOI: 10.1021/acs.oprd.8b00424, 2019.03.
3. Masanao Sawa, Shotaro Miyazaki, Ryohei Yonesaki, Hiroyuki Morimoto, Takashi Ohshima, Catalytic Enantioselective Decarboxylative Mannich-Type Reaction of N-Unprotected Isatin-Derived Ketimines, Org. Lett. 2018, 20, 5393–5397, DOI:10.1021/acs.orglett.8b02306, 2018.08.
4. Ryohei Yonesaki, Yuta Kondo, Walaa Akkad, Masanao Sawa, Kazuhiro Morisaki, Hiroyuki Morimoto, Takashi Ohshima, 3‐Mono‐Substituted BINOL Phosphoric Acids as Effective Organocatalysts in Direct Enantioselective Friedel‐Crafts‐Type Alkylation of N‐Unprotected α‐Ketiminoester, Chem. Eur. J. 2018, 24, 15211–15214, DOI:10.1002/chem.201804078, 2018.08.
5. Hao Luo, Kensuke Nishii, Shusei Ishikura, Anthony Swain, Naoyuki Morishige Ryo Yazaki, Takashi Ohshima, Senji Shirasawa, Toshiyuki Tsunoda, Growth suppression of human colorectal cancer cells with mutated KRAS by 3-deaza-cytarabine in 3d floating culture, Anticancer research 2018, 38, 4247–4256., DOI: 10.21873/anticanres.12721, 2018.07.
6. Tsukushi Tanaka, Kayoko Hashiguchi, Takafumi Tanaka, Ryo Yazaki, Takashi Ohshima, Chemoselective Catalytic Dehydrogenative Cross-Coupling of 2-Acylimidazoles: Mechanistic Investigations and Synthetic Scope, ACS Catal. 2018, 8, 8430–8440, DOI:10.1021/acscatal.8b02361, 2018.07, Chemoselective iron-catalyzed dehydrogenative cross-coupling using 2-acylimidazoles is described. The addition of a phos-phine oxide ligand substantially facilitated the generation of tert-butoxy radicals from di-tert-butyl peroxide, allowing for efficient benzylic C–H bond cleavage under mild conditions. Extensive mechanistic studies revealed that the enolization of 2-acylimidazole proceeded through dual iron catalyst activation, followed by subsequent chemoselective cross-coupling with a benzyl radical over an undesired benzyl radical-derived homo-coupling dimer that inevitably formed in earlier reported con-ditions. A variety of alkylarenes, aliphatic alkane and functionalized 2-acylimidazoles were applicable, demonstrating the synthetic utility of the present catalysis. Contiguous all-carbon quaternary carbons were constructed through dehydrogenative cross-coupling for the first time. The catalytic chemoselective activation of 2-acylimidazole over bidentate coordinative and much more acidic malonate diester was particular noteworthy. Catalytic oxidative cross-enolate coupling of two distinct car-boxylic acid equivalents was also achieved using acetonitrile as a coupling partner..
7. Takafumi Tanaka, Tsukushi Tanaka, Taro Tsuji, Ryo Yazaki, Takashi Ohshima, Strategy for Catalytic Chemoselective Cross-Enolate Coupling Reaction via a Transient Homocoupling Dimer, Org. Lett. 2018, 20, 3541–3544., 10.1021/acs.orglett.8b01313, 2018.05.
8. Kazuhiro Morisaki, Hiroyuki Morimoto, Mashima, Kazushi, Takashi Ohshima, Development of Direct Enantioselective Alkynylation of α-Ketoester and α-Ketiminoesters Catalyzed by Phenylbis(oxazoline)Rh(III) Complexes, Journal of Synthetic Organic Chemistry, Japan, 2018, 76, 226–240, 10.5059/yukigoseikyokaishi.76.226, 2018.03.
9. Matsumoto Yohei, Nakatake Daiki, Ryo Yazaki, Takashi Ohshima, An Expeditious Route to trans-Configured Tetrahydrothiophenes Enabled by Fe(OTf)3-Catalyzed [3+2] Cycloaddition of Donor–Acceptor Cyclopropanes with Thionoesters. , Chem. Eur. J. 2018, 24, 6062–6066, 10.1002/chem.201800957, 2018.02.
10. Watanabe Kenji, Ohshima Takashi, Bioconjugation with Thiols by Benzylic Substitution, Chem. Eur. J. 2018, 24, 3959–3964, 2018.02, タンパク質などの生体由来の分子と合成分子を結びつける手法に生体共役反応があります。医 薬の分野において幅広く用いられており、抗体と薬物の複合体や生命機能を解明するための分子 を合成する上で欠かす事ができません。多くの場合、高い反応性を持つことから、タンパク質中 に含まれるチオール基が生体共役反応の反応点としてよく用いられてきました。しかし、これ までに開発されてきた反応は適用可能な水素イオン濃度指数(pH)に制限があり、pH によっては チオール基の空気酸化、チオールの付加物からのチオール基の脱離が起こるなど問題点がありま した。
今回我々は、これまで生体共役 反応の反応点として用いられてこなかったベンジリック型水酸基に着目しました。ベンジリッ ク型水酸基が適切に配置された反応剤(図)を用いる事で、チオール基の空気酸化が起こらない 弱酸性条件の下で生体共役反応を開発することに成功しました。本反応剤は、中性やアルカリ性 条件ではベンジリック位水酸基が活性化されないため、チオールやアミンと反応せず、弱酸性条件でチオールとのみ特異的に反応しました。反応によって生成したチオールの付加物は、他のチオール類が共存する条件でもチオール基の交換を起こさず、安定に存在しました。さらに、本反応が実際に様々なタンパク質のチオール基の修飾に適用可能であることを見出し、タンパク質への機能性分子の導入にも成功しました。.
11. Das Amrita, Watanabe Kenji, Morimoto Hiroyuki, Ohshima Takashi, Boronic Acid Accelerated Three-Component Reaction for the Synthesis of α-Sulfanyl-Substituted Indole-3-acetic Acids, Org. Lett. 2017, 19, 5794–5797, 2017.10.
12. Sawa Masanao, Morisaki Kazuhiro, Kondo Yuta, Morimoto Hiroyuki, Ohshima Takashi, Direct Access to N-Unprotected α- and/or α-Tetrasubstituted Amino Acid Esters via Direct Catalytic Mannich-Type Reactions Using N-Unprotected Trifluoromethyl Ketimines, Chem. Eur. J. 2017, 23, 17022–17028., 2017.09, 不斉四置換炭素を持つ非天然アミノ酸類は、天然由来のアミノ酸類とは異なる特性を有し、医薬品や生物活性物質の合成において重要な化合物の1つです。この非天然アミノ酸類の化学合成法の1つとして、ケチミンとカルボニル化合物との反応が世界中で研究されてきました。しかし、これまでの合成法では窒素原子があらかじめ保護されたケチミンを用いており、不要な保護基の着脱が必要となるため合成効率の面で改善の余地を残していました。
 今回、我々は金属触媒を用いることで、窒素原子が無保護のケチミンに対する反応が原子効率100%で円滑に進行し、不斉四置換炭素を持つ様々な窒素上無保護の非天然アミノ酸類を直接合成可能であることを実証しました。また、本反応が有機触媒を用いて不斉合成へと適用可能であることも見出し、種々の不斉四置換炭素を有する非天然アミノ酸類の立体選択的な合成も達成しました。さらに、連続した不斉四置換炭素を有する窒素上無保護の非天然アミノ酸類の立体選択的な直接合成にも世界で初めて成功しました。.
13. Morisaki Kazuhiro, Kondo Yuta, Sawa Masanao, Morimoto Hiroyuki, Ohshima Takashi, Synthesis of 1-Tetrasubstituted 2,2,2-Trifluoroethylamine Derivatives via Palladium-Catalyzed Allylation of sp3 C–H Bonds, Chem. Phar. Bull. 2017, 65, 1089–1092., 2017.11.
14. Kazuhiro Morisaki, Hiroyuki Morimoto, Takashi Ohshima, Direct access to N-unprotected tetrasubstituted propargylamines via direct catalytic alkynylation of N-unprotected trifluoromethyl ketimines, Chem. Commun. 2017, 53, 6319–6322., 2017.04, 医薬品などの原料として有用な化合物にアミン類があります。イミンに対する付加反応は、 種々のアミン類を効率的に合成することができるため、世界中で研究が行われてきました。しか し、これまで開発された反応は、反応性・選択性の制御や生成物の安定性の面から窒素原子があ らかじめ保護されたイミン (N-protected imines) を用いるのが常識でした。そのため、合成素子として有用な無保護のアミン類を得るためには不要な保護基を取り除く必要があり、合成工程数 や環境調和性の面で改善の余地を残していました。
今回我々は、 これまであまり用いられてこなかった窒素原子が保護されていないイミン (N-unprotected imines) を用いることで、保護基を不要とする新しい無保護アミン類の合成手法を確立すること に成功しました。大嶋教授・森本講師らは、窒素原子が保護されていないイミンが末端アルキン*2 の付加反応に利用可能であることを見出し、容易に入手可能な亜鉛試薬とカルボン酸を組み合わ せた新たな触媒によって、種々の無保護アミン類を直接的かつ効率的に合成することに成功しま した(下図)。また、得られた無保護アミン類が生物活性物質の誘導体へと直接変換可能であるこ とも実証しました。.
15. Seiya Taninokuchi, Ryo Yazaki, Takashi Ohshima, Chemoselective α-Oxidation of Acylpyrazoles en Route to α-Hydroxy Acid Derivatives, Org. Lett., 2017, 19 (12), pp 3187–3190, DOI: 10.1021/acs.orglett.7b01293, 2017.03.
16. Toru Deguchi, Hai-Long Xin, Hiroyuki Morimoto, Takashi Ohshima, Direct Catalytic Alcoholysis of Unactivated 8-Aminoquinoline Amides, ACS Catal. 2017, 7, 3157–3161., DOI: 10.1021/acscatal.7b00442, 2017.03, アミドはタンパク質や高分子、生理活性物質などに広くみられる重要な構造の1つです。近年は有機化合物の炭素—水素結合官能基化反応における合成中間体としても注目されていますが、活性化されていないアミド結合の切断はその安定性の高さから一般に困難であり、強酸や強塩基などの厳しい条件が必要なため、官能基共存性に改善の余地を残していました。また、近年アルコールを用いる触媒的切断手法も開発されていましたが、アミド型配向基を直接切断可能な反応は報告がありませんでした。今回我々は、アミド型配向基として数多く利用されている8-アミノキノリンアミドについてアルコールによる切断反応の検討を行った結果、入手容易で水や空気に安定なニッケル触媒が有効に機能することを見出し、対応するエステルへの変換を達成しました。本反応は、炭素—水素結合官能基化反応の生成物に対しても有効に機能し、グラムスケール合成への適用や配向基の回収も可能でした。また、既存の切断反応では実現困難な高い官能基共存性や化学選択性も実現しており、同分野で開発した鉄(III)サレン触媒を用いることでアルコールの適用基質の拡大にも成功していることから、多様な構造を有するエステルの合成への応用も期待されます。.
17. Kazuhiro Morisaki, Hiroyuki Morimoto, Kazushi Mashima, Takashi Ohshima, DIRECT ENANTIOSELECTIVE ALKYNYLATION OF α-KETOESTERS AND α-KETIMINOESTERS CATALYZED BY [BIS(OXAZOLINE)PHENYL] RHODIUM(III) COMPLEXES, Heterocycles 2017, 95, 637–661., 2017.01.
18. Renshi Li, Tomoki Takeda, Takashi Ohshima, Hideyuki Yamada, Yuji Ishii, Metabolomic profiling of brain tissues of mice chronically exposed to heroin, Drug Metab. Pharmacokinet. 2017, 32, 108–111, DOI: 10.1016/j.dmpk.2016.10.410, 2017.02.
19. Zhao Li, Masamichi Tamura, Ryo Yazaki, Takashi Ohshima, Catalytic Chemoselective Conjugate Addition of Amino Alcohols to α,β-Unsaturated Ester: Hydroxy Group over Amino Group and Conjugate Addition over Transesterification., Chem. Pharm. Bull. 2017, 65, 19–21, DOI: 10.1248/cpb.c16-00333, 2017.01.
20. Megumi Noshita, Yuhei Shimizu, Hiroyuki Morimoto, Takashi Ohshima, Diethylenetriamine-Mediated Direct Cleavage of Unactivated Carbamates and Ureas, Org. Lett. 2016, 18, 6062–6065, DOI: 10.1021/acs.orglett.6b03016, 2016.11.
21. Yumi Yamamoto, Jun Arai, Takuya Hisa, Yohei Saito, Takahiro Mukai, Takashi Ohshima, Minoru Maeda, Isomeric iodinated analogs of nimesulide: synthesis, physicochemical characterization, cyclooxygenase-2 inhibitory activity, and transport across Caco-2 cells, Bioorg. Med. Chem. 2016, 24, 3727–3733., DOI: org/10.1016/j.bmc.2016.06.015, 2016.06.
22. Daiki Nakatake, Ryo Yazaki, Takashi Ohshima, Chemoselective Transesterification of Acrylate Derivatives for Functionalized Monomer Synthesis Using a Hard Zinc Alkoxide Generation Strategy, Eur. J. Org. Chem. 2016, 10.1002/ejoc.201600737, 2016.07.
23. Zhao Li, Ryo Yazaki, Takashi Ohshima, Chemo- and Regioselective Direct Functional Group Installation through Catalytic Hydroxy Group Selective Conjugate Addition of Amino Alcohols to α,β-Unsaturated Sulfonyl Compounds, Org. Lett. 2016, 10.1021/acs.orglett.6b01464, 2016.06.
24. Rikiya Horikawa, Chika Fujimoto, Ryo Yazaki, Takashi Ohshima, μ-Oxo-Dinuclear Iron(III) Catalyzed O-Selective Acylation of Aliphatic and Aromatic Amino Alcohols and Transesterification of tert-Alcohols, Chem. Eur. J. 2016, 10.1002/chem.201602801, 2016.06, 我々は、従来の触媒では達成困難であったエステル合成を可能とする高活性鉄触媒の開発に成功しました。 エステルは医薬品などの様々な機能成分子が含まれるためその合成法の研究が盛んに行われてきました。近年ではグリーンケミストリーの観点から「触媒」を用いたエステル合成法が多く研究されています。しかし用いることのできる原料に制限があり、特に立体障害の大きなエステルの触媒的合成法の開発が強く望まれていました。今回本研究グループでは、これまで困難であった原料を用いたエステル合成を可能とする高活性鉄触媒の開発に成功しました。例えば、安価なメチルエステルから合成化学上有用なtert-ブチルエステルを合成することが可能であり、これは世界で初めての成功例です。tert-ブチルエステルはアミノ酸のペプチド合成やポリエステルなどの高分子材料の合成で非常に重要です。また私たち独自の化学選択的な反応においても、より精密な制御が要求される活性エステルを原料として用いることが可能で、様々な医薬品を原料として用いることもでき、芳香族アミノアルコールの水酸基選択的アシル化も世界初となります。.
25. Kazuhiro Morisaki, Masanao Sawa, Ryohei Yonesaki, Hiroyuki Morimoto, Kazushi Mashima, Takashi Ohshima, Mechanistic Studies and Expansion of the Substrate Scope of Direct Enantioselective Alkynylation of α-Ketiminoesters Catalyzed by Adaptable (Phebox)Rh(III) Complexes, J. Am. Chem. Soc. 2016, DOI: 10.1021/jacs.6b01590, 2016.06, 今回我々は、α位二置換非天然アミノ酸誘導体の不斉合成に有効な末端アルキンの触媒的付加反応の反応機構解析および適応範囲の拡大に成功しました。 α位二置換非天然アミノ酸は、生体内での生物学的安定性の観点などからペプチド医薬品の原料としての利用が期待されています。我々は以前の研究で、環境調和性に優れたα位二置換非天然アミノ酸合成に有効である、ロジウム触媒による末端アルキンの直接的付加反応を見出していました。本反応の詳細な反応機構解析の結果、より高活性な新規触媒を見いだし、反応性の向上・触媒量の低減化・適応範囲の拡大に成功しました。これにより、種々のα位二置換非天然アミノ酸誘導体の効率的合成が可能となりました。.
26. Daiki Nakatake, Ryo Yazaki, Yoshimasa Matsushima, Takashi Ohshima, Transesterification Reaction Catalyzed by Recyclable Heterogeneous Zinc/Imidazole Catalyst, Adv. Synth. Catal. 2016, 10.1002/adsc.201600229, 2016.06.
27. Kazushi Agura, Yukiko Hayashi, Mari Wada, Daiki Nakatake, Kazushi Mashima, Takashi Ohshima, Studies of the Electronic Effects of Zinc Cluster Catalysts and their Application to the Transesterification of β-Keto Esters, Chem. Asian J. 2016, 10.1002/asia.201600062, 2016.04.
28. Keisuke Tokumasu, Ryo Yazaki, Takashi Ohshima, Direct Catalytic Chemoselective α-Amination of Acylpyrazoles: A Concise Route to Unnatural α-Amino Acid Derivatives, J. Am. Chem. Soc., 2016, 138, 2664–2669. , 10.1021/jacs.5b11773, 2016.02.
29. Daiki Nakatake, Yuki Yokote, Yoshimasa Matsushima, Ryo Yazaki, Takashi Ohshima, A highly stable but highly reactive zinc catalyst for transesterification supported by a bis(imidazole) ligand, Green Chem., 2016, Advance Article, DOI: 10.1039/C5GC02056E , 10.1039/C5GC02056E, 2015.10.
30. Ming Zhang, Kenji Watanabe, Masafumi Tsukamoto, Ryozo Shibuya, Hiroyuki Morimoto, Takashi Ohshima, A Short Scalable Route to (−)-α-Kainic Acid Using Pt-Catalyzed Direct Allylic Amination, Chemistry - A European Journal, DOI: 10.1002/chem.201406557, Volume 21, Issue 10, pages, 3937-3941, 2015.03, An increased supply of scarce or inaccessible natural products is essential for the development of more sophisticated pharmaceutical agents and biological tools, and thus the development of atom-economical, step-economical and scalable processes to access these natural products is in high demand. Herein we report the development of a short, scalable total synthesis of (−)-α-kainic acid, a useful compound in neuropharmacology that is, however, limited in supply from natural resources. The synthesis features sequential platinum-catalyzed direct allylic aminations and thermal ene-cyclization, enabling the gram-scale synthesis of (−)-α-kainic acid in six steps and 34 % overall yield..
31. Yuhei Shimizu, Megumi Noshita, Yuri Mukai, Hiroyuki Morimoto, Takashi Ohshima, Cleavage of unactivated amide bonds by ammonium salt-accelerated hydrazinolysis (Backcover), Chem. Commun. , DOI: 10.1039/C4CC02014F , 50, 12623-12625, 2014.05.
32. Ryozo Shibuya, Lu Lin, Yasuhito Nakahara, Kazushi Mashima, Takashi Ohshima, Dual Platinum and Pyrrolidine Catalysis in the Direct Alkylation of Allylic Alcohols: Selective Synthesis of Monoallylation Products, Angew. Chem. Int. Ed., 10.1002/anie.201311200, 53, 4377–4381, 2014.04, A dual platinum- and pyrrolidine-catalyzed direct allylic alkylation of allylic alcohols with various active methylene compounds to produce products with high monoallylation selectivity was developed. The use of pyrrolidine and acetic acid was essential, not only for preventing undesirable side reactions, but also for obtaining high monoallylation selectivity.(Article first published online: 6 MAR 2014).
33. Hiroyuki Morimoto, Risa Fujiwara, Yuhei Shimizu, Kazuhiro Morisaki, Takashi Ohshima, Lanthanum(III) Triflate Catalyzed Direct Amidation of Esters, Org. Lett., 10.1021/ol500593v, 16, 2018–2021., 2014.03.
34. Shuhei Uesugi, Zhao Li, Ryo Yazaki, Takashi Ohshima, Chemoselective Catalytic Conjugate Addition of Alcohols over Amines., Angew. Chem. Int. Ed., 10.1002/anie.201309755, 53, 1611–1615., 2014.02, A highly chemoselective conjugate addition of alcohols in the presence of amines is described. The cooperative nature of the catalyst enabled chemoselective activation of alcohols over amines, allowing the conjugate addition to soft Lewis basic α,β-unsaturated nitriles. Divergent transformation of the nitrile functionality highlights the utility of the present catalysis.(Article first published online: 22 JAN 2014).
35. Kazuhiro Morisaki, Masanao Sawa, Jun-ya Nomaguchi, Hiroyuki Morimoto, Yosuke Takeuchi, Kazushi Mashima, Takashi Ohshima, Rh-Catalyzed Direct Enantioselective Alkynylation of α-Ketiminoesters, Chem. Eur. J. , 19,(26), 8417-8420, 2013.06, A green way to amino acids: α-Tetrasubstituted α-amino acid derivatives are formed in high yield and enantioselectivity by using a Rh-catalyzed enantioselective alkynylation of α-ketiminoesters. This reaction, which involves a proton transfer and can be conducted at room temperature, has high substrate scope (see scheme; Cbz=benzyloxycarbonyl, Fmoc=9-fluorenylmethyloxycarbonyl)..
36. Yukiko Hayashi,, Stefano Santoro, Yuki Azuma, Fahmi Himo, Takashi Ohshima, Kazushi Mashima, Enzyme-like Catalysis via Ternary-Complex Mechanism: Alkoxy-bridged Dinuclear Cobalt Complex Mediates Chemoselective O-Esterification over N-Amidation, J. Am. Chem. Soc., 10.1021/ja400367h, 135, 16, 6192-6199, 2013.03.
37. Takashi Ohshima, Kazushi Mashima, Platinum-Catalyzed Direct Amination of Allylic Alcohols, Journal of Synthetic Organic Chemistry, Japan , 10.1002/anie.201202354, 70, 1145-1156, 2012.07.
38. Takashi Ohshima, Junji Ipposhi, Yasuhito Nakahara, Ryozo Shibuya, Kazushi Mashima, Aluminum Triflate as a Powerful Catalyst for Direct Amination of Alcohols, Including Electron-Withdrawing Group-Substituted Benzhydrols, Adv. Synth. Catal., 10.1002/adsc.201200536, 354, 2447-2452, 2012.08.
39. Yuhei Shimizu, Hiroyuki Morimoto, Ming Zhang, Takashi Ohshima, Microwave-Assisted Deacylation of Unactivated Amides to Amines Using Ammonium Salt-Accelerated Transamidation, Angew. Chem. Int. Ed, 10.1002/anie.201202354, 51, 8564-8567, 2012.07, Deacylation of unactivated amides to give amines is a fundamental reaction in organic chemistry, but classical hydrolysis of amides generally requires harsh reaction conditions, i.e., strong acids or bases at high temperature, because amide bonds are chemically robust due to delocalization of the electrons in amides. Although a number of reports have been published to overcome the problems, these methods have limitations such as the use of moisture-sensitive reagents and substrate specificity. Therefore, there is need for developing a practical and efficient method to promote deacylation of unactivated amides to produce amines under mild conditions.

Transamidation is another method to cleave amide bonds to give amines, which could be performed under milder conditions than hydrolysis because amine is more nucleophilic than water. However, reported transamidations were mostly limited to the reactions of primary amides to give secondary or tertiary amides or an intramolecular variant with the release of ring strains, both of which could not be applied for deacylation of amines. Although Gellman and Stahl reported aluminum or zirconium amide-catalyzed intermolecular transamidations of secondary and tertiary amides, these catalytic methods suffer from producing equilibrium mixtures of starting and targeting materials as well as sensitivity to acidic functionalities. Thus, practical application of transamidation for the deacylation of unactivated amides to amines requires further development.

In this paper, we describe microwave-assisted deacylation of unactivated amides to amines using ammonium salt-accelerated transamidation. The reactions proceed under mild conditions (as low as 50°C) with simple and readily available ammonium salts and ethylenediamine as reagents without special care regarding air and moisture. This method is applicable to a variety of acylated amines and compatible with a wide range of functional groups, including unprotected carboxylic acid, phenol, and indole, as well as acid-labile MOM, MEM, and THP groups, and a base-labile TIPS group. Such acylated amines are well utilized in asymmetric hydrogenation of enamides and kinetic resolution as well as C–H activation reactions in recent years.
.
40. Nagano, Takuto, Iimuro, Atsuhiro, Takashi Ohshima, Kita, Yusuke, Mashima, Kazushi, Asymmetric Autoinduction in Hydrogenation of 2-Substituted Quinoxalines Catalyzed by Iridium Complexes bearing Chiral Diphosphine Ligand, Chem. Eur. J., 10.1002/chem.201201366, 18, 11578-11592, 2012.08.
41. Cartigny, Damien, Berhal, Farouk, Nagano, Takuto, Phansavath, Phannarath, Ayad, Tahar, Genêt, Jean-Pierre, Takashi Ohshima, Mashima, Kazushi, Ratovelomanana-Vidal Virginie, Highly Efficient and General Asymmetric Hydrogenation of 2-Alkyl- and 2-Aryl-Substituted Quinoxaline Derivatives Catalyzed by Iridium-Difluorphos: Halide Effect and Synthetic Application, J. Org. Chem, 10.1021/jo300455y, 77, 4544-4556, 2012.04.
42. Takashi Ohshima, Yukiko Hayashi,, Kazushi Agura, Yuka Fujii, Asako Yoshiyama, Kazushi Mashima, Sodium methoxide: a simple but highly efficient catalyst for the direct amidation of esters, Chem. Commun., 10.1039/c2cc32153j, 48, 5434-5436, 2012.04, A simple NaOMe catalyst provides superior accessibility to a wide variety of functionalized amides including peptides through direct amination of esters in an atom-economical and environmentally benign way..
43. Yang, Yi; Hayashi, Yukiko; Fujii, Yuka; Nagano, Takuto; Kita, Yusuke; Ohshima, Takashi; Okuda, Jun; Mashima, Kazushi, Efficient cyclic carbonate synthesis catalyzed by zinc cluster systems under mild conditions., Catal. Sci. Tech., 10.1039/C1CY00404B, 2, 509-513, 2011.11, An efficient catalytic system of zinc cluster and tetrabutylammonium iodide (TBAI) was developed for cyclic carbonates synthesis from epoxides and carbon dioxide (CO2) without utilization of any organic solvents under very mild conditions (25 oC, 1 atm), even when impurities such as water and air contaminated. .
44. Das, Kalpataru; Shibuya, Ryozo; Nakahara, Yasuhito; Germain, Nicolas; Ohshima, Takashi; Mashima, Kazushi, Platinum-Catalyzed Direct Amination of Allylic Alcohols with Aqueous Ammonia for Selective Synthesis of Primary Allylamines., Angew. Chem. Int. Ed., 10.1002/anie.201106737, 51, 150-154, 2011.11, Direct amination of unactivated allylic alcohols with aqueous ammonia was catalyzed by Pt–DPEphos complex to give the corresponding allylamines along with water as a sole co-product. Under optimized conditions, primary allylamines were obtained as major products with excellent monoallylation selectivity (90:10 ~ >99:1). Aqueous conditions were essential for achieving primary allylamines in high yield..
45. Maegawa, Yusuke; Agura, Kazushi; Hayashi, Yukiko; Ohshima, Takashi; Mashima, Kazushi, Transesterification of α-Amino Esters Catalyzed by a Tetranuclear Zinc Custer, Zn4(OCOCF3)6O., Synlett, 10.1055/s-0031-1290096, 23, 137-141, 2011.09, In the presence of a Zn cluster catalyst, alcohols are efficiently converted to the corresponding acetate just by refluxing in EtOAc. The mild reaction conditions enabled the reactions of various functionalized alcohols to proceed in good to high yield. Moreover, even when a high excess of the acetyl donor is used, the hydroxyl groups are selectively acetylated in the presence of highly nucleophilic aliphatic amino groups, shch chemoselectivity being similarly to enzymatic reaction..
46. Maegawa, Yusuke; Ohshima, Takashi; Hayashi, Yukiko; Agura, Kazushi; Iwasaki, Takanori; Mashima, Kazushi, Additive Effect of N-Heteroaromatics on Transesterification Catalyzed by Tetranuclear Zinc Cluster., ACS Catal., org/10.1021/cs200224b, 1, 1178-1182, 2011.08, A catalytic amount of 4-dimethylaminopyridine showed drastic additive effects on transesterification catalyzed by the μ4-oxo-tetranuclear zinc cluster Zn4(OCOCF3)6O (1a), enhancing the catalytic activity by more than 15-fold. The new catalyst system facilitates transesterification of less reactive sterically demanding esters and alcohols..
47. Takashi Ohshima, Direct substitution of the hydroxy group with highly functionalized nitrogen nucleophiles catalyzed by Au(III)., Chem. Commun., 10.1039/c1cc12760h, 47, 8322-8234, 2011.06, A direct catalytic substitution of various allylic and benzylic alcohols with synthetically useful, but acid-sensitive Boc, Bus, and Dios protected amine nucleophiles, which have not been well utilized for Lewis acid catalysis, with various functionalities (OTBS, OTHP, etc.) were efficiently catalyzed by 1 mol% of Au(III) under mild conditions..
48. T. Ohshima, T. Kawabata, Y. Takeuchi, T. Kakinuma, T. Iwasaki, T. Yonezawa, H. Murakami, H. Nishiyama, K. Mashima, C1-Symmetric Rh-Phebox-Catalyzed Asymmetric Alkynylation of α-Keto Ester, Angew. Chem. Int. Ed., 10.1002/anie.201100252, accepted, 2011.05, Bifunctional Acid/Base Rh Catalyst: A newly developed C1-symmetric Rh-Phebox complex efficiently catalyzed an asymmetric alkynylation of α-keto ester with various aryl and alkyl substituted terminal alkynes to provide the corresponding chiral tertiary propargylic alcohols with up to 99% ee..
49. Y. Hayashi, T. Ohshima, Y. Fujii, Y. Matsushima, K. Mashima, Trifluoroacetic Acid Adduct of Trifluoroacetate-Bridged μ4-Oxo-Tetranuclear Zinc Cluster, Zn4(OCOCF3)6O•CF3CO2H: Synthesis under Mild Conditions and Catalytic Transesterification and Oxazoline Formation, Catal. Sci. Tech., 1, 230-233, 2011.01, Synthesis of a trifluoroacetate-bridged tetranuclear zinc cluster and its trifluoroacetic acid (TFA) adduct under mild conditions (~110 ˚C) was achieved. The catalytic activity and functional group tolerance of the TFA adduct in transesterification and oxazoline formation were almost identical to those of the original zinc cluster..
50. T. Iwasaki, K. Agura, Y. Maegawa, Y. Hayashi, T. Ohshima, K. Mashima, A Tetranuclear Zinc Cluster-Catalyzed Practical and Versatile Deprotection of Acetates and Benzoates, Chem. Eur. J., 16, 11567-11571, 2010.08.
51. D. Cartigny, T. Nagano, T. Ayad, J.-P. Genêt, T. Ohshima, K. Mashima, V. Ratovelomanana-Vidal, Iridium-Difluorphos Catalyzed Asymmetric Hydrogenation of 2-Alkyl and 2-Aryl-Substituted Quinoxalines: A General and Efficient Route into Tetrahydroquinoxalines, Adv. Synth. Catal., 352, 1886-1891, 2010.07.
52. T. Ohshima, H. Tadaoka, K. Hori, N. Sayo, K. Mashima, Highly Enantio- and s-trans C–C Double Bond Selective Catalytic Hydrogenation of Cyclic Enones: Alternative Synthesis of (–)-Menthol, Chem. Eur. J., 10.1002/chem.200701505, 14, 2060-2066, 14, 2060-2066 (2008), 2010.07.
53. T. Ohshima, T. Iwasaki, Y. Maegawa, A. Yoshiyama, K. Mashima, Enzyme-like Chemoselective Acylation of Alcohols in the presence of Amines Catalyzed by a Tetranuclear Zinc Cluster, J. Am. Chem. Soc., 10.1021/ja711349r, 130, 2945-2946, 130, 2944-2945 (2008), 2008.03.
54. T. Iwasaki, Y. Maegawa, Y. Hayashi, T. Ohshima, K. Mashima, Transesterification of Various Methyl Esters Under Mild Conditions Catalyzed by Tetranuclear Zinc Cluster, J. Org. Chem., 10.1021/jo800625v, 73, 5147-5150, 73, 5147-5150 (2008), 2008.06.
55. A. Sniady, A. Durham, M. S. Morreale, A. Marcinek, S. Szafert, T. Lis, K. R. Brzezinska, T. Iwasaki, T. Ohshima, K. Mashima, R. Dembinski, Zinc-Catalyzed Cycloisomerizations. Synthesis of Substituted Furans and Furopyrimidine Nucleosides, J. Org. Chem., 10.1021/jo8007995, 73, 5881-5889, 73, 5881-5889 (2008), 2008.07.
56. T. Iwasaki, Y. Maegawa, Y. Hayashi, T. Ohshima, K. Mashima, A Simple, General, and Highly Chemoselective Acetylation of Alcohols Using Ethyl Acetate as the Acetyl Donor Catalyzed by a Tetranuclear Zinc Cluster, Synlett, 10.1055/s-0029-1217335, 10, 1659-1663, 1659-1663 (2009).
57. 大嶋孝志、岩崎孝紀、真島和志, 亜鉛四核クラスター錯体による 環境調和型触媒反応の開発, 有機合成化学協会誌, 67, 5, 491-506, 2009.05.
58. T. Ohshima, Y. Yamamoto, U. Takaki, Y. Inoue, T. Saeki, K. Itou, Y. Maegawa, T. Iwasaki, K. Mashima, Theoretical Study of Al(III)-Catalyzed Conversion of Glyoxal to Glycolic Acid: Dual Activated 1,2-Hydride Shift Mechanism by Protonated Al(OH)3 Species, Chem. Commun., 10.1039/b902729g, 2688–2690, 2009, 2688–2690.
59. H. Tadaoka, D. Cartigny, T. Nagano, T. Gosavi, T. Ayad, J.-P. Genêt, T. Ohshima, V. Ratovelomanana-Vidal, K. Mashima, Unprecedented Halide Dependence on Catalytic Asymmetric Hydrogenation of 2-Aryl- and 2-Alkyl-substituted Quinolinium Salts Using Ir–DIFLUORPHOS Halide Complexes, Chem. Eur. J.,, 10.1002/chem.200901477, 15, 9990 – 9994, 2009, 15, 9990 – 9994.
60. T. Ohshima, Y. Miyamoto, J. Ipposhi, Y. Nakahara, M. Utsunomiya, K. Mashima, Platinum-Catalyzed Direct Amination of Allylic Alcohols under Mild Conditions: Ligand and Microwave Effects, Substrate Scope, and Mechanistic Study, J. Am. Chem. Soc., 10.1021/ja9046075, 131, 14317–14328, 2009.09.
61. H. Shimizu, T. Nagano, N. Sayo, T. Saito, T. Ohshima, K. Mashima, Asymmetric Hydrogenation of Heteroaromatic Ketones and Cyclic and Acyclic Enones Mediated by Cu(I)–Chiral Diphosphine Catalysts, Synlett, 10.1055/s-0029-1218347, 19, 3143–3146, 2009.08.

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