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Organocatalysis with Chiral Formamides: Asymmetric Allylation and Reduction of Imines
Author(s) -
Baudequin Christine,
Chaturvedi Devdutt,
Tsogoeva Svetlana B.
Publication year - 2007
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200700058
Subject(s) - chemistry , formamides , enantioselective synthesis , aldimine , organocatalysis , amine gas treating , formamide , yield (engineering) , medicinal chemistry , moiety , catalysis , organic chemistry , materials science , metallurgy
Simple aldimine, derived from p ‐nitrobenzaldehyde and 2‐aminophenol, reacts with allyltrichlorosilane in the presence of chiral N ‐formylproline activator 5 and an L ‐proline additive to afford the corresponding homoallylic amine in good yield (84 %) and with moderate enantioselectivity (43 % ee ). The role of the second formamide moiety in the activator is crucial to bring about the enhancement in the reaction rate and enantioselectivity, as C 2 ‐chiral bisformamide 1 promotes for the same allylation reaction in higher yield (94 %) and enantioselectivity (83 % ee ). Chiral monoformamide 5 (10 mol‐%), with the assistance of HMPA as an additive, also catalyses the asymmetric reduction of ketimine 13 in the presence of trichlorosilane in good yield and enantioselectivity (75 %, 81 % ee ). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)