Copper(II)-Catalyzed β-Borylation of Acetylenic Esters in Water

Abstract

A method for the β-borylation of alkynoates has been developed. In the presence of bis(pinacolato)diboron and catalytic amounts of both copper(II) and 4-picoline, substituted alkynoates undergo borylation in a regio-, stereo-, and chemoselective fashion. The reaction is performed under mild conditions using water as solvent and open to the atmosphere to exclusively afford (Z)-β-boryl-α,β-unsaturated esters.

Key words

boron - copper - stereoselectivity - hydroboration - alkynes

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