State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China.
Collaborative Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin, 300071, China.
Angew Chem Int Ed Engl. 2018 Feb 5;57(6):1650-1653. doi: 10.1002/anie.201710128. Epub 2018 Jan 16.
The benzylic functionalization of alkylpyridines is an important pathway for pyridine derivatives synthesis. The reaction partners, however, were mostly limited to highly reactive polar electrophiles. Herein, we report a potassium amide-catalyzed selective benzylic C-H bond addition of alkylpyridines to styrenes. Potassium bis(trimethylsilyl)amide (KHMDS), a readily available Brønsted base, showed excellent catalytic activity and chemoselectivity. A series of alkylpyridine derivatives, including benzylic quaternary carbon substituted pyridines, were obtained in good to high yield. Preliminary mechanistic studies revealed that the deprotonation equilibrium is probably responsible for the excellent selectivity.
烷基吡啶的苄基官能化是吡啶衍生物合成的重要途径。然而，反应伙伴大多仅限于高反应性的极性亲电试剂。在此，我们报告了一种钾酰胺催化的选择性苄基 C-H 键加成反应，用于烷基吡啶与苯乙烯的反应。钾双（三甲基硅基）酰胺（KHMDS）是一种易得的布朗斯台德碱，显示出优异的催化活性和化学选择性。一系列烷基吡啶衍生物，包括苄基季碳取代的吡啶，以良好至高产率得到。初步的机理研究表明，去质子化平衡可能是优异选择性的原因。
