Science of Synthesis

Takaya, J.; Iwasawa, N., Science of Synthesis: C-1 Building Blocks in Organic Synthesis, (2014) 1, 302.

Hydrocarboxylation and the related sila- and boracarboxylation of alkynes have been developed using a copper catalyst. In 2011, the group of Tsuji first reported hydrocarboxylation of alkynes catalyzed by N-heterocyclic carbene–copper fluorides ‌61‌–‌63‌ utilizing a hydrosilane as the stoichiometric reductant.[‌46‌] The reaction proceeds mainly with internal alkynes with 1–2.5 mol% of catalyst under 1 atmosphere carbon dioxide, affording various α,β-unsaturated carboxylic acids ‌64‌ in good yield and regioselectivity (‌Scheme 20‌). It should be noted that the reaction employs a mild and easy-to-handle hydrosilane as a reducing reagent in contrast to other examples described previously, which use strong and air-sensitive reducing reagents such as triethylaluminum and diethylzinc.

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References