A Concise and Versatile Double-Cyclization Strategy for the Highly Stereoselective Synthesis and Arylative Dimerization of Aspidosperma Alkaloids

Abstract

Building cycles: A strategy for the concise, stereoselective synthesis of aspidosperma alkaloids and related structures via a common putative diiminium ion intermediate is reported. The approach enables the dimerization of aspidosperma-type structures at the sterically hindered C2 position. The intermediate is prepared in one step from the shown lactam through an electrophilic double-cyclization cascade (see scheme; Tf=trifluoromethanesulfonyl).