Transforming benzylideneamine N,C-chelate boron compounds to BN-cycloocta-/cyclohepta-trienes bearing a tetrasubstituted BN unit via photoisomerization

Abstract

A series of benzylideneamine N,C-chelate boron compounds have been found to undergo rapid multistructural transformations with UV irradiation, yielding new BN-cycloocta-1,3,6-triene ((4Z,6Z)-1,2,3,8-tetrahydro-1,2-azaborocine) and BN-cyclohepta-1,3,5-triene (2,7-dihydro-1H-1,2-azaborepine) derivatives with a tetrasubstituted BN unit quantitatively. The simple imine donor also lends itself to achieving photoreactivity in compounds with two phenyl substituents on boron, which is the first example for this type of organoboron photochemistry.