Electrophile-Induced Ring Expansions of <i>β</i>-Lactams toward γ-Lactams
作者:Willem Van Brabandt、Norbert De Kimpe
DOI:10.1021/jo0509556
日期:2005.10.1
was developed from 4-(1-chloroalkyl)azetidin-2-ones. Starting from the latter β-lactams, a new synthesis of pyrrolidin-2-ones was achieved. When 4-isopropenylazetidin-2-ones were treated with bromine in dichloromethane, diastereoselective electrophile-induced ring expansions toward 5-bromopyrrolidin-2-ones were performed. Further oxidation of 3-benzyloxypyrrolidin-2-ones with bromine toward 3-bromopyrrolidin-2-ones