Chiral tertiary boronic esters have been shown to be useful intermediates in organic synthesis, as they can undergo a variety of functional group transformations, for example, conversion to alcohols, amines, quaternary centers, or aryldialkylmethines with high stereospecificity. [1] Recently, such intermediates have become available in high ee through two distinct methods: 1) borylation of Michael acceptors [2] or allylic electrophiles, [3] and 2) lithiation-borylation of secondary benzylic carbamates (Scheme 1), [4] which can deliver exceptionally high enantioselectivities over a broad range of substrates (> 99.1 e.r.).

An original­ syn: The first enantioselective Suzuki–Miyaura cross‐coupling of chiral, enantioenriched secondary allylic boronic esters is described (see scheme; DME=dimethoxyethane, Bpin = pinacolboryl, dba = dibenzylideneacetone). Mechanistic studies show that the reactions proceed via γ‐selective transmetalation followed by reductive elimination. The reaction provides the first independent confirmation that the transmetalation of boronic esters proceeds via a syn pathway.

A convenient method for the copper(II)-catalyzed direct arylation of cyclic and nonaromatic enamides using diaryliodonium salts has been developed. The reaction demonstrates large functional group tolerance, good yields, and total regioselectivity with a C(3)-functionalization. The synthetic potential of this coupling was explored by using a range of readily accessible diaryliodonium salts and enamides.