Boryl substitution on an olefin activates the olefinic double bond toward a
ddition of an organozinc reagent. Addition of an allylic zinc reagent to an
alkenylboronate thus takes place smoothly to afford a variety of gem-zinci
o/boryl species. Theoretical studies with density functional calculations o
n the reaction pathway revealed that the reaction proceeds via a zincio-ene
reaction rather than a bora-Claisen rearrangement.