- Catalytic enantioselective C-H functionalization of indoles with α-diazopropionates using chiral dirhodium(II) carboxylates: Asymmetric synthesis of the (+)-α-methyl-3-indolylacetic acid fragment of acremoauxin A
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An enantioselective C-H functionalization of N-methoxymethyl (MOM)-protected 2,3-unsubstituted indoles with α-diazopropionates has been effected via catalysis by dirhodium(II) tetrakis[N-phthaloyl-(S)- triethylalaninate], Rh2((S)-PTTEA)4, providing α-methyl-3-indolylacetates in high yields and with enantioselectivities of up to 86% ee. The effectiveness of this protocol was demonstrated by the first catalytic asymmetric synthesis of the (+)-α-methyl-3-indolylacetic acid fragment of acremoauxin A, a potent plant-growth inhibitor. Furthermore, the Fujioka protocol using a combination of TMSOTf and 2,2′-bipyridyl was shown to be superior for the removal of the N-MOM group.
- Goto, Takayuki,Natori, Yoshihiro,Takeda, Koji,Nambu, Hisanori,Hashimoto, Shunichi
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p. 907 - 915
(2011/08/09)
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- Synthesis of Acremoauxin A, a New Plant Growth Regulator Produced by Acremonium roseum I 4267
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Acremoauxin A, a new fungal auxin derivative produced by A. roseum I 4267, was synthesized from indole, lactic acid, and D-mannitol. (+)-2-(3-Indolyl)propionic acid was prepared from its synthetic racemate by biological resolution using the acremoauxin-producing fungus.The synthetically confirmed structure of acremoauxin A was 1-O--D-arabitol (1).
- Yoshida, Noriyuki,Sassa, Takeshi
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p. 2681 - 2683
(2007/10/02)
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