Atroposelective Synthesis of Axially Chiral Styrenes by Platinum- Catalyzed Stereoselective Hydrosilylation of Internal Alkynes.

Abstract

Hydrofunctionalization of alkynes is one of the most efficient ways to access axially chiral styrenes with open-chained olefins. While great advances have been achieved for 1-alkynylnaphthalen-2-ols and analogues, atroposelective hydrofunctionalization of unactivated internal alkynes lags. Herein we reported a platinum-catalyzed atroposelective hydrosilylation of unactivated internal alkynes for the first time. With monodentate TADDOL-derived phosphonite L1 used as a chiral ligand, various axially chiral styrenes were achieved in excellent enantioselectivities with high E-selectivities. Control experiments showed that the NH-arylamide groups have significant effects on both the yields and enantioselectivities and could act as directing groups. The potential utilities of the products were shown by the transformations of the amide motifs of the products.