Realization of complete regiochemical control during the conversion of squarate esters into complex linear and angular polyquinanes. The consequences of incorporating a leaving group into one of the alkenyllithium reactants

摘要

A useful method is presented for controlling whether linear or angular triquinanes are formed during a reaction cascade initiated by the 2-fold addition of alkenyl anions to diisopropyl squarate. The key feature of the process involves the incorporation of a leaving group into one of the original Nucleophilic reagents. Placement of the nucleofuge within a cyclic anion leads ultimately to Formation of a linear product.