Asymmetric synthesis of the tricyclic core of calyciphylline A-type alkaloids via intramolecular [3 + 2] cycloaddition

Article abstract of DOI:10.1021/ol403609c

Asymmetric synthesis of the [5-6-7] tricyclic system common to the Calyciphylline A-type alkaloids is reported, featuring Overman rearrangement, Heck cyclization, intramolecular [3 + 2] cycloaddition, diastereoselective hydrogenation, and Claisen rearrangement as strategic events. The approach is capable of installing the crucial carbonyl functionality as well as multiple stereogenic centers within a congested polycyclic ring skeleton.