Unexpected boratranes: BBr3 mediated synthesis and mechanistic insights

Boratranes synthesis are predictably based on the reactions of triethanolamine derivatives with boric acid, or trialkyl borate and require prolonged heating reagents under reflux. Herein, authors report an efficient unexpected boratranes featuring one hand three six-membered chelating ring two five-membered other a trans-annular boron atom is bound to nitrogen, oxygen carbon atom. These novel have been synthetized by reacting N,N-bis(2-methoxybenzyl) alkynylamines BBr3 in dichloromethane at low temperature. The reaction mechanism was investigated using density functional theory (DFT) calculations. A mechanistic pathway proceeding through key dioxazaborecinium intermediate proposed. This alternative protocol represents convenient access dissymmetric functionalizable mild conditions good yields.