Contrasting Diastereoselectivity between Cyclic Nitrones and Azomethine Ylides. Stereocontrolled Pathways to cis-anti-anti-cis-Oxazatetraquinanes from a Bicyclic Nitrone.

A study of [3 + 2] cycloaddition reactions of a bicyclic nitrone with various cyclopentenes has clarified the diastereomeric preferences as a function of the olefinic structure. It has also identified an important stereochemical difference between nitrones and the analogous azomethine ylides in [3 + 2] cycloaddition reactions.