Asymmetric synthesis of (2-carbamoyloxy-1-alkenyl)cyclopropanes by intramolecular cycloalkylation
作者:Sven Brandau、Dieter Hoppe
DOI:10.1016/j.tet.2005.09.110
日期:2005.12
Enantioenriched, diastereomerically pure (2-carbamoyloxy-1-alkenyl)cyclopropanes 22 are easily prepared via deprotonation of different allyl carbamates with n-butyllithium and (−)-sparteine (4). The mechanism of the cyclization reaction was determined and several substituted (S)-configured vinylcyclopropanes 32 were synthesized by two different methods. The configurational stability of the intermediate