Palladium-catalyzed alkyne hydrocarbonylation under atmospheric pressure of carbon monoxide in the presence of hydrosilane?

Green Chemistry Pub Date: 2023-01-13 DOI: 10.1039/D2GC04689J

Abstract

An ultramild reaction condition for the hydrocarbonylation of alkynes, which is performed under atmospheric pressure of CO in the absence of acids, has been developed. Palladium hydride (Pd-H) generated from triethylsilane (Et3SiH) rather than the traditionally used strong acid (HX) is applied for the first time in this transformation. In addition, an unusual counteranion-controlled linear and branch selectivity for terminal alkynes is observed under otherwise identical conditions. A wide range of 1,1-, 1,2-, and 1,2,2-substituted α,β-unsaturated thioesters or amides are regioselectively obtained from terminal and internal alkynes in moderate to excellent yields. Furthermore, the first enantioselective construction of indolone derivatives with a C–N chiral axis is achieved when using 2-(tert-butyl)-N-(2-alkynylphenyl)aniline as the substrate in the presence of TMS-SYNPHOS as the chiral ligand.

Graphical abstract: Palladium-catalyzed alkyne hydrocarbonylation under atmospheric pressure of carbon monoxide in the presence of hydrosilane
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