Enantioselective nucleophile-catalyzed cycloadditions

Abstract

Chapter 1 describes the development of an asymmetric nucleophile-catalyzed [2+2] cycloaddition of ketenes with aldehydes. This is the first report of a catalytic enantioselective synthesis of trisubstituted [beta]-lactones. Two enantioselective phosphine-catalyzed [3+2] cycloadditions of allenoates are detailed in Chapter 2. A method for the asymmetric synthesis of cyclopentenes via a [3+2] cycloaddition of allenoates with enones is first discussed. This is followed by a report of our efforts to extend this [3+2] methodology to imine electrophiles. We conclude, in Chapter 3, with an account of the development of a novel phosphine-catalyzed synthesis of bicyclo[3.3.0]octanones and bicyclo[4.3.0]nonanones. Preliminary results for an enantioselective variant of this method are also disclosed.