C−C Bond Formation of Benzyl Alcohols and Alkynes Using a Catalytic Amount of KOtBu: Unusual Regioselectivity through a Radical Mechanism

Waste not, want not: Benzyl alcohols underwent C−C bond formation with alkynes under thermal conditions in the presence of a catalytic amount of KO^tBu to provide α‐alkylated ketones with 100 % atom economy (see scheme). The reaction showed unusual regioselectivity to give products in which the C=O group was located on the side of the molecule derived from the alcohol.

Abstract

We report a C−C bond‐forming reaction between benzyl alcohols and alkynes in the presence of a catalytic amount of KO^tBu to form α‐alkylated ketones in which the C=O group is located on the side derived from the alcohol. The reaction proceeds under thermal conditions (125 °C) and produces no waste, making the reaction highly atom efficient, environmentally benign, and sustainable. Based on our mechanistic investigations, we propose that the reaction proceeds through radical pathways.

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