Phosphine-catalyzed anti-carboboration of alkynoates with alkyl-, alkenyl-, and arylboranes.

ABSTRACT

We found that trialkylphosphine organocatalysts promoted unprecedented anti-carboboration of alkynoates with alkyl-, alkenyl-, or arylboranes to form ß-boryl acrylates. The regioselectivity of the carboboration across the polar C-C triple bond exhibited inverse electronic demand, with the less electronegative B atom being delivered to the positively charged ß carbon atom. The regioselectivity and the anti stereoselectivity were both complete and robust. In addition, the substrate scope was broad with excellent functional group compatibility.