Rhodium-Catalyzed B–H Activation of 1,2-Azaborines: Synthesis and Characterization of BN Isosteres of Stilbenes

Alec N. Brown, Lev N. Zakharov, Tanya Mikulas, David A. Dixon, Shih-Yuan Liu
2014 Organic Letters  
The first example of catalytic B−H activation of azaborines leading to a new family of stilbene derivatives through dehydrogenative borylation is reported. Ten 1,2azaborine-based BN isosteres of stilbenes have been synthesized using this method, including a BN isostere of a biologically active stilbene. It is demonstrated that BN/CC isosterism in the context of stilbenes can lead to significant changes in the observed photophysical properties such as higher quantum yield and a larger Stokes
more » ... t. Direct comparative analysis of BN stilbene 3g and its carbonaceous counterpart 6g is consistent with a stronger charge-transfer character of the excited state exhibited by 3g in which the 1,2-azaborine heterocycle serves as a better electron donor than the corresponding arene.
doi:10.1021/ol501362w pmid:24916200 pmcid:PMC4068778 fatcat:fv4yewxjj5g47b5c22gje2ffri