Synthesis of Highly Congested Tertiary Alcohols via the [3,3] Radical Deconstruction of Breslow Intermediates

Abstract

Pericyclic processes such as [3,3]-sigmatropic rearrangements leading to the rapid generation of molecular complexity constitute highly valuable tools in organic synthesis. Herein, we report the formation of particularly hindered tertiary alcohols via rearrangement of Breslow intermediates formed in situ from readily available N-allyl thiazolium salts and benzaldehyde derivatives. Experimental mechanistic studies performed suggest that the reaction proceeds via a close radical pair which recombine in a regio- and diastereoselective manner, formally leading to [3,3]-rearranged products.

Synthesis of Highly Congested Tertiary Alcohols via the [3,3] Radical Deconstruction of Breslow Intermediates

“…In summary, we report a simple and efficient synthesis of highly congested tertiary homoallylic alcohols via the rearrangement of Breslow intermediates formed in situ from simple N -allyl thiazolium salts and benzaldehyde derivatives . Experimental mechanistic studies suggest that the reaction likely proceeds via homolytic fragmentation of the Breslow intermediate into a close radical pair which can recombine in a regio- and diastereoselective manner, formally leading to [3,3]-rearranged products.…”