Lithium alkyl assisted coupling of a 2-cyano-2,3-dihydro-1H-1,3,2-diazaborole to give tBuNCHCHN(tBu)BC(iPr)N–BN(tBu)CHCHNtBu

Abstract

Reaction of 2-cyano-1,3,2-diazaborole ^tBuNCHCHN(^tBu)BCN (2) with half an equivalent of isopropyllithium afforded compound ^tBuNCHCHN(^tBu)BC(ⁱPr)N–BN(^tBu)CHCHN^tBu (7). In contrast to this, a 1 ∶ 1 stoichiometry of the reactants led to ^tBuNCHCHN(^tBu)BⁱPr (6) as the product of a nucleophilic substitution process at the boron atom. Similarly, regardless of the molar ratio of reactants employed, treatment of 2 with cyclopropyllithium, isobutyllithium or phenyllithium afforded solely substitution products ^tBuNCHCHN(^tBu)BR [R = cPr (12); Ph (13); ⁱBu (14)].