Exo-Selective and Enantioselective Photoenolization/Diels–Alder Reaction

An unusual exo-selective photoenolization/Diels–Alder reaction of electron-rich 2-methylbenzaldehydes and dienophiles containing a benzoyl group at its α position was reported herein. The chiral TADDOL-type ligand plays a key role in this process: (1) accelerating the reaction; (2) controlling the enantioselectivity; and (3) improving and tuning the diastereoselectivity of the reaction.本文报道了一类不同寻常的外选择性光烯醇化/Diels-Alder（Diels-Alder）反应，其底物为富电子2-甲基苯甲醛与α位含苯甲酰基的亲双烯体。手性TADDOL型配体在该反应中发挥关键作用：(1) 加速反应进程；(2) 调控对映选择性；(3) 优化并调节反应的非对映选择性。