General ppm-level Pd-catalysed asymmetric diarylalkyne hydrosilylation to access structurally diverse Si-stereogenic vinylsilanes

Abstract

Alkyne hydrosilylation represents a straightforward method to synthesize vinylsilanes, which have found numerous applications in synthetic chemistry and materials science. However, it is challenging to produce silicon-stereogenic hydrosilanes through catalytic asymmetric hydrosilylation of prochiral dihydrosilanes with internal diarylalkynes. Herein, we present a highly efficient palladium-catalyzed asymmetric hydrosilylation of general internal diarylalkynes with different symmetric or asymmetric aryl groups, each proceeding through the desymmetrization of prochiral dihydrosilanes. The efficiency of this approach is systematically demonstrated for the first time in the synthesis of chiral-at-silicon organosilicon compounds bearing various aromatic groups with high enantioselectivity (up to 97% ee), which would be challenging to produce by means of traditional synthetic methods. Unique efficiency and reaction results for the chiral ligand-controllable hydrosilylation reaction of alkynes were also described using a ppm-level Pd catalyst. To date, this is the most efficient palladium-based catalyst system for the catalytic asymmetric hydrosilylation of alkynes.