Chiral 3-hydroxypyrrolidin-2-ones.: Part 2:: Stereodivergent synthesis of conformationally restricted analogues of β-homoserine

Starting from the homochiral 3-1-butyldimethylsilyloxypyrrolidin-2-one 2, a stereodivergent synthetic route was developed leading to both 3,4-trans- and 3,4-cis-3-amino-4-hydroxymethyl pyrrolidin-2-ones, 19 and 28, that are conformationally restricted analogues of beta-homoserine 4. In addition, with a large number of 3,4-disubstituted pyrrolidin-2-ones in hand, a trend was observed for both H-3 chemical shifts and J(3,4) values, allowing the configuration to be assigned to either 3-hydroxy or 3-amino derivatives. (C) 2005 Elsevier Ltd. All rights reserved.