Catalyst-free construction of spiro [benzoquinolizidine-chromanones] via a tandem condensation/1,5-hydride transfer/cyclization process

Abstract

A catalyst-free tandem 1,5-hydride shift/cyclization process to form spiro [benzoquinolizidine-chromanones] is developed, which features high atom- and step-economy, high levels of stereocontrol, mild conditions, and a simple workup process. A series of new polycyclic spiro [benzoquinolizidine-chromanones] were obtained in high yields with excellent diastereoselectivities (up to 91% yield, >20 : 1 dr).