Synthesis, structural characterization, and reactivity of 1,3,2,5-diazadiborinine

Abstract

Because of the isoelectronic and isostructural relationships between a carbon-carbon double bond (C=C) and a boron-nitrogen single bond (B-N), the substitution a B-N unit for a C=C unit is considered to be one of the important strategies, and this method will form and expand the diversity of aromatic molecules. My thesis mainly focused on the isolation, characterization and relative reactivity of 1,3,2,5-diazadiborinine C. Because compound C possess both a nucleophilic (Lewis base) and an electrophilic (Lewis acid) boron centre in the B2N2C2 six-membered ring, it can activate MeOTf, PhC≡CH, CO2 and alkene derivatives without any catalysts. Notably, the reaction between C and CO2 or alkene derivatives underwent reversible [4+2] cycloaddition reactions to afford the corresponding compounds. The addition reaction of a series of sp, sp2 and sp3 hybridized carbanions to C affords isolable ionic species, which can be regarded as Janovsky-type complexes. Moreover, C can also serve as a pre-catalyst to promote hydroboration of carbonyl compounds as well as carbon dioxide, in which the actual active catalyst is the adduct of C with carbonyls or CO2, respectively.