PUB - Publikationen an der Universität Bielefeld

Carbenes are well established reactive intermediates and play an important role in organic synthesis, whereas the scope of borylenes is rather limited. Selective borylene insertion into a C–N bond to yield boryl‐functionalized N‐heterocyclic olefins (NHOs), [{N(Dipp)N(DippBH)CHCH}CCH2]2 (6) and [{N(Dipp)N(DippBPh)CHCH}CCH2][{N(Dipp)N(2‐iPr‐6‐CHMeCH2BC6H3)CHCH}CCH2] (8) (Dipp = 2,6‐iPr2C6H3) is reported for the first time. KC8 reduction of (IPrCH2)BRX2 adducts (IPrCH2 = {N(Dipp)CH}2CCH2; R = X = I (2); R = Ph, X = Cl (4)) affords compounds 6 and 8. Surprisingly, treatment of (IPrCH2)BHCl2 (3) with KC8 yields completely unexpected diborane compound (IPr)BH2BH2(IPr) (7). Compound 2 is unstable in THF and induces ring opening reaction to form the borenium ion [(IPrCH2)B{O(CH2)4I}2]I (5)