We have observed that α-borylcarbanion, generated in situ from the reaction of 1,1-diborylalkane with an alkoxide base, could facilitate an unprecedented base-promoted deborylative alkylation of N-heteroarenes. The reaction proceeds efficiently for a wide range of N-heteroarenes and 1,1-diborylalkanes with excellent regioselectivity. The reaction also can be applied for the direct introduction of a methyl group to 9-O-methylquinine N-oxide, thus it can serve as a powerful method for late-stage functionalization. Moreover, a new transition-metal-free borylation of aryl and vinyl halides using 1,1-diborylalkanes as boron sources is also developed. In this transformation one of the boron groups from 1,1-diborylalkanes is selectively transferred to aryl and vinyl halides in the presence of sodium tert-butoxide as the only activator to form organoboronate esters. Under the developed borylation conditions, a broad range of organohalides are borylated with excellent chemoselectivity and functional group compatibility, thus offering a rare example of a transition-metal-free borylation protocol.

We have observed that the chemoselective transmetalation of 1,1-diborylalkanes with copper catalyst can be achieved in the presence of alkoxide base. The generated a-borylalkylcopper species underwent a highly chemo- and diastereoselective alkylation of N–tert-butanesulfinyl aldimines with diborylmethane to form chiral β-aminoboronates, which are valuable synthetic building blocks in organic synthesis. The developed copper-catalytic system was also extended to a copper-catalyzed SN2′-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. This method provided an useful approach to afford branched alkylboronate esters.