Asymmetric Synthesis of Multifunctionalized 2,3-Benzodiazepines by a One-Pot N‑heterocyclic Carbene/Chiral Palladium Sequential Catalysis

We report the first example of the construction of chiral 2,3-benzodiazepine compounds which are of biologic and pharmaceutical relevance by asymmetric catalysis. Catalyzed by a thiazolium-derived carbene and a palladium-chiral bidentate phosphine complex in sequence, one-pot reaction between 1-(2-(2-nitrovinyl)­aryl)­allyl esters 1 with azodicarboxylates 2 took place efficiently at ambient temperature to produce 4-nitro-1-vinyl-1H-2,3-benzodiazepine-2,3-dicarboxylates 5 in good to excellent yields with an enantiomeric ratio of up to 95:5.本研究首次报道了通过不对称催化策略构建具有生物学与药学价值的手性2,3-苯二氮䓬类化合物的实例。在噻唑鎓衍生卡宾与钯-手性双齿膦配合物依次催化下，1-(2-(2-硝基乙烯基)芳基)烯丙基酯1与偶氮二羧酸酯2于室温下发生高效一锅法反应，以良好至优异的收率得到4-硝基-1-乙烯基-1H-2,3-苯二氮䓬-2,3-二羧酸酯5，其对映体比例最高可达95:5。