Boron-Substituted 1,3-Dihydro-1,3-azaborines: Synthesis, Structure, and Evaluation of Aromaticity

摘要

BN/CC isosterism has emerged as an attractive strategy to expand the chemical space of compounds relevant to biomedical research and materials science. Among the three BN isosteres of benzene (i.e., 1,2-dihydrido-1,2-azabor-ine, 1,3-dihydrido-1,3-azaborine, and 1,4-dihydrido-1,4-aza-borine; see Scheme 1), 1,3-dihydro-1,3-azaborine (abbrevi-ated herein as 1,3-azaborine) is thermodynamically the least stable isomer. Not surprisingly, its development has lagged behind that of the other azaborines in the series. The first synthetic example of a 1,3-azaborine was reported in late 2011, and the diversity of synthetically accessible 1,3-azaborines remains very limited to date.