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C 2 ‐Symmetrical Pyrrolidine Derivatives Chiral Auxiliaries in Radical Chemistry
Author(s) -
Veit Andres,
Lenz Roman,
Seiler Martin E.,
Neuburger Markus,
Zehnder Margareta,
Giese Bernd
Publication year - 1993
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19930760128
Subject(s) - chemistry , pyrrolidine , chiral auxiliary , stereochemistry , tin , alkylation , organic chemistry , medicinal chemistry , catalysis , enantioselective synthesis
Fumaramides 3b and 3c bearing the C 2 ‐symmetrical pyrrolidine moieties (2 R ,5 R )‐2,5‐bis(methoxymethyl)pyrrolidine ( 2b ) or 1,3:4,6‐di‐ O ‐benzylidene‐2,5‐dideoxy‐2,5‐imino‐ L ‐idit ( 2c ), respectively, as a chiral auxiliary lead to high diastereoselectivities in radical reactions (‘tin method’; Scheme 1 ). Removal of the chiral auxiliaries affords the corresponding alkylated fumaric acids Scheme 2 . Single‐crystal X‐ray structures of 3b and 3c support arguments that lead to the model of 1,4‐stereoinduction.