Koji Takeda

Publications (5)40.38 Total impact

• Article: Continuous flow system with a polymer-supported dirhodium(II) catalyst: application to enantioselective carbonyl ylide cycloaddition reactions.

  Koji Takeda, Tadashi Oohara, Naoyuki Shimada, Hisanori Nambu, Shunichi Hashimoto
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  ABSTRACT: The immobilization of [Rh(2) (S-PTTL)(S-TCPTTL)(3) ] (PTTL = N-phthaloyl-tert-leucinate, TCPTTL=N-tetrachlorophthaloyl-tert-leucinate) has been accomplished by copolymerization of the Rh(II) -complex-containing monomer with 2-(trifluoromethyl)styrene and a flexible cross-linker. The immobilized catalyst promoted intermolecular carbonyl ylide cycloaddition reactions in CF(3) C(6) H(5) under continuous flow conditions, where high yields as well as high levels of enantioselectivity and turnover number were achieved.
  Chemistry 11/2011; 17(50):13992-8. · 5.93 Impact Factor
• Article: Highly enantioselective cyclopropenation reaction of 1-alkynes with α-alkyl-α-diazoesters catalyzed by dirhodium(II) carboxylates.

  Takayuki Goto, Koji Takeda, Naoyuki Shimada, Hisanori Nambu, Masahiro Anada, Motoo Shiro, Kaori Ando, Shunichi Hashimoto
  Angewandte Chemie International Edition 06/2011; 50(30):6803-8. · 13.45 Impact Factor
• Article: A Short, Catalytic, Asymmetric Synthesis of Diospongins A and B by a One‐Pot, Sequential Hetero‐Diels–Alder/Mukaiyama–Michael Reaction Process

  Masahiro Anada, Takuya Washio, Yudai Watanabe, Koji Takeda, Shunichi Hashimoto
  Annalen der Chemie und Pharmacie 10/2010; 2010(35):6850 - 6854. · 3.10 Impact Factor
• Article: A polymer-supported chiral dirhodium(II) complex: highly durable and recyclable catalyst for asymmetric intramolecular C-H insertion reactions.

  Koji Takeda, Tadashi Oohara, Masahiro Anada, Hisanori Nambu, Shunichi Hashimoto
  Angewandte Chemie International Edition 09/2010; 49(39):6979-83. · 13.45 Impact Factor
• Article: Catalytic asymmetric synthesis of the endo-6-aryl-8-oxabicyclo[3.2.1]oct-3-en-2-one natural product from Ligusticum chuanxing via 1,3-dipolar cycloaddition of a formyl-derived carbonyl ylide using Rh2(S-TCPTTL)4.

  Naoyuki Shimada, Taiki Hanari, Yasunobu Kurosaki, Koji Takeda, Masahiro Anada, Hisanori Nambu, Motoo Shiro, Shunichi Hashimoto
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  ABSTRACT: The reaction of a six-membered cyclic formyl-carbonyl ylide derived from alpha-diazo-beta-ketoester with phenylacetylene derivatives under the catalysis of dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], Rh(2)(S-TCPTTL)(4), provides cycloadducts containing an 8-oxabicyclo[3.2.1]octane ring system in up to 97% ee. This represents the first example of an enantioselective 1,3-dipolar cycloaddition of a cyclic formyl-carbonyl ylide. Using this catalytic process, an asymmetric synthesis of endo-6-aryl-8-oxabicyclo[3.2.1]oct-3-en-2-one natural product 1 from Ligusticum chuanxing Hort. has been achieved.
  The Journal of Organic Chemistry 09/2010; 75(17):6039-42. · 4.45 Impact Factor