[3,3] Sigmatropic Rearrangement of Boron‐Containing Allyl Alcohols: Synthesis of Allyl Addition Reagents

Enantiomerically pure reagents for allyl additions were prepared by [3,3] sigmatropic rearrangements (see scheme) followed by a separation of the diastereoisomers. The highly stable allylboronic esters with a stereogenic center α to a boron atom were used to synthesize Z-configured homoallylic alcohols with an enantiomeric excess >94 %.