Pd-catalyzed allylic alkylation cascade with dihydropyrans: regioselective synthesis of furo[3,2-c]pyrans

Org Lett. 2013 May 17;15(10):2430-3. doi: 10.1021/ol400902d. Epub 2013 Apr 26.

Abstract

A regioselective palladium-catalyzed allylic alkylation cascade forms furo[3,2-c]pyrans from various cyclic β-dicarbonyl bis-nucleophiles and 3,6-dihydro-2H-pyran bis-electrophiles. The combination of allylic carbonate and anomeric siloxy leaving groups in the dihydropyran substrate allows control of the many regiochemical possibilities in this reaction. Annulation proceeds stereoconvergently to give cis-fused furopyrans from either cis- or trans-substituted starting material.