Paderborn University, Chemistry Department, Warburger-Strasse 100, D-33098 Paderborn, Germany.
Org Lett. 2021 May 7;23(9):3626-3630. doi: 10.1021/acs.orglett.1c01018. Epub 2021 Apr 12.
The borane-catalyzed synthesis of dihydroquinoline-4-ones is developed. The amino-substituted chalcones undergo a 1,7-hydride shift upon Lewis acid activation to form a zwitterionic iminium enolate, which collapses to the dihydroquinoline-4-one scaffold. The reaction proceeds in high yields (75-99%) with an excellent diastereoselectivity of up to >99:1 (:). The reaction mechanism is investigated by kinetic, isotope labeling, and computational experiments.
硼烷催化合成二氢喹啉-4-酮。在路易斯酸活化下，氨基取代的查尔酮发生 1,7-氢迁移，形成两性离子亚胺烯醇化物，然后缩合形成二氢喹啉-4-酮骨架。该反应以高产率（75-99%）和极好的非对映选择性（高达>99:1）进行。通过动力学、同位素标记和计算实验研究了反应机理。
