Synthesis of Branched Alkylboronates by Copper-Catalyzed Allylic Substitution Reactions of Allylic Chlorides with 1,1-Diborylalkanes

Reported herein is a copper-catalyzed S(N)2'-selective allylic substitution reaction using readily accessible allylic chlorides and 1,1-diborylalkanes, a reaction which proceeds with chemoselective C-B bond activation of the 1,1-diborylalkanes. In the presence of a catalytic amount of [Cu(IMes) Cl] [IMes=1,3-bis(2,4,6-trimethylphenyl) imidazole-2-ylidene] and LiOtBu as a base, a range of primary and secondary allylic chlorides undergo the S(N)2'-selective allylic substitution reaction to produce branched alkylboronates. The synthetic utilities of the obtained alkylboronates are also presented.