Asymmetric Synthesis of α‐Substituted Allyl Boranes and Their Application in the Synthesis of Iso‐agatharesinol

Use your borane: A stereocontrolled synthesis of allyl boranes from chiral sulfur ylides and their subsequent reaction with aldehydes to give homoallylic alcohols is described. The allyl boranes also could undergo a stereospecific 1,3-borotropic rearrangement to give another set of homoallylic alcohols (see scheme). The reaction has been applied to an efficient synthesis of iso-agatharesinol.