Shuang Li, Pengpeng Zhang, Yuanhe Li, Shumin Lu, Jianxian Gong*, and Zhen Yang*

Org. Lett., 2017, 19,  4416

A cascade benzenethiol-mediated intramolecular [3 + 2] cycloaddition reaction between an allene and an α,β-unsaturated aldehyde or ester is developed for the diastereoselective synthesis of [3.3.0] bicyclic system bearing two quaternary atoms at their bridgehead positions. Notably, these structurally complex systems can be found in a wide range of natural products.