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The Effect of Lewis Acids on the Stereochemistry in the Ugi Three‐Component Reaction with D ‐ lyxo ‐Pyrroline
Author(s) -
Bonger Kimberly M.,
Wennekes Tom,
Filippov Dmitri V.,
Lodder Gerrit,
van der Marel Gijsbert A.,
Overkleeft Herman S.
Publication year - 2008
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.200800340
Subject(s) - chemistry , ugi reaction , isocyanide , pyrroline , lewis acids and bases , aldehyde , imine , stereochemistry , wittig reaction , organic chemistry , catalysis
A library of polyhydroxylated pyrrolidines was obtained by performing a tandem Staudinger/aza‐Wittig/Ugi three‐component reaction on a L ‐ribose‐derived 4‐azido aldehyde. In this paper we describe the effect of Lewis acids on the diastereoselectivity of the final Ugi three‐component reaction step that the intermediate ( D ‐ lyxo ‐pyrroline) cyclic imine undergoes. When the Ugi reaction was performed in methanol almost exclusively pyrrolidines with a 2,3‐ cis relationship were formed. However, a significant amount of 2,3‐ trans product was formed upon addition of Lewis acids to the Ugi reaction mixture. The scope of this effect is explored by evaluating a diverse set of Lewis acids in combination with variation of other reaction parameters and the carboxylic acid/isocyanide component. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)