Tandem [5,5]-/[3,3]- rearrangements of aryl sulfoxides with allyl nitriles

Abstract

Tandem aromatic rearrangements can redirect the regioselectivity of original rearrangement and increase the complexity of products. Despite their obvious synthetic value, only few protocols of tandem aromatic rearrangements are reported. In this Article, we describe two new tandem aromatic rearrangements by using sulfonium rearrangements. Specifically, [5,5]-rearrangement of phenyl sulfoxides with allyl nitriles followed by [3,3]-Cope rearrangement forges the tandem [5,5]-/[3,3]-rearrangements which affords ortho-functionalized phenyl sulfides as products. The other tandem rearrangement proceeds through [5,5]-rearrangement of phenyl sulfoxides with allyl nitriles and the subsequent nuclephilic addition/DDQ-oxidation induced [3,3]-Cope rearrangement, which eventually achieves meta-functionalized phenyl sulfides as products.