Enantioselective Radical Type, 1,2-Oxytrifluoromethylation of Olefins Catalyzed by Chiral Vanadyl Complexes: Importance of Noncovalent Interactions
作者:Chien-Tien Chen、Yu-Cheng Su、Chia-Hao Lu、Chien-I Lien、Shiang-Fu Hung、Chan-Wei Hsu、Rachit Agarwal、Ramuasagar Modala、Hung-Min Tseng、Pin-Xuan Tseng、Ryoma Fujii、Kyohei Kawashima、Seiji Mori
DOI:10.1021/acscatal.1c01813
日期:2021.6.18
2-oxytrifluoromethylations of styrenes were explored by using N-oxyphthalimide (NOPI) as the resulting benzylic radical anchor after cross-coupling by a CF3 radical under the catalyses of chiral N-salicylidene-derived oxovanadium(V) complexes. Among the 15 different solvents and 15 different catalysts examined, the best scenarios were in i-PrOH with C3-tert-butyl or C3-fluoro-/2,5-dimethylphenyl-substituted vanadyl
在手性N-水杨烯衍生的氧钒 (V)催化下,通过 CF 3自由基交叉偶联后,使用N-氧邻苯二甲酰亚胺 (NOPI) 作为所得苄基自由基锚,探索了苯乙烯的不对称三组分 1,2-氧三氟甲基化复合体。在检查的 15 种不同溶剂和 15 种不同催化剂中,最佳方案是在i -PrOH 中使用 C3-叔丁基或 C3-氟-/2,5-二甲基苯基取代的氧钒催化剂,导致相应的互补S和R产物的产率分别高达 88% 和 87/86% ee,单次重结晶后进一步富集到至少 94% ee。测试 ccontrol α-(2-苯基环丙基)苯乙烯以证明涉及苄基自由基物质的不对称事件。DFT计算表明,苄基基团的SOMO被放置在一个方式来定向CF 3 CH 2组从远叔丁基组中的salicylidene-升-叔通过与相互作用-butylglycinate模板Ñ NOPI的-氧原子以双分子均裂取代(S H2)类型机制。对映选择性分布主要由中间钒