Regio- and diastereoselective synthesis of <i>trans</i>-3,4-diaryldihydrocoumarins <i>via</i> metal-free [4+2] annulation of ynamides with <i>o</i>-hydroxybenzyl alcohols

Abstract

An efficient regio- and diastereoselective method for the construction of valuable trans-3,4-diaryldihydrocoumarins via metal-free [4+2] annulation of ynamides with o-hydroxybenzyl alcohols has been developed. Ynamides are first treated as 2-π partners to react with o-hydroxybenzyl alcohols via traceless sulfonamide directing groups, affording trans-3,4-diaryldihydrocoumarins in good yields with high regio- and diastereoselectivities. This metal-free methodology is also characterized by a wide substrate scope, good functional group tolerance, and efficiency on a gram scale.

Topics & Concepts