Evaluation of the aromaticity of borepin: Synthesis and properties of 1-substituted borepins

Article abstract of DOI:10.1021/om00032a051

The reaction of 1,1-dibutylstannepin with BCl₃ gave 1-chloroborepin, which has been converted to a variety of 1-substituted borepins, C₆H₆BX, where X = OH, O_1/2, OCH₃, 2,4,6-Me₃C₆H₂, CH₂CH₂CH₂NMe₂, F, NH₂, N(CH₂)₅, N(iPr)₂, H. 1-Chloroborepin and 1-aminoborepin have been investigated by ab initio methods. All borepins have been studied using ¹H NMR, ¹¹B NMR, and ¹³C NMR spectroscopy. The X-ray crystal structure of 1-chloroborepin gives evidence of a π-delocalized structure. All properties are discussed in terms of the aromatic character of the borepin ring system.