Ring‐Opening Lithiation–Borylation of 2‐Trifluoromethyl Oxirane: A Route to Versatile Tertiary Trifluoromethyl Boronic Esters
作者:Meganathan Nandakumar、Belén Rubial、Adam Noble、Eddie L. Myers、Varinder K. Aggarwal
DOI:10.1002/anie.201912797
日期:2020.1.13
and agrochemical discovery. Here, we show that lithiation-borylation reactions of 2-trifluoromethyl oxirane give densely functionalized and highly versatile trifluoromethyl-substituted α-tertiary boronic esters. The intermediate boronate complexes undergo the desired 1,2-rearrangement of the carbon-based group with complete retentive stereospecificity, a process that was only observed in non-polar solvents
立体异构的三氟甲基取代的碳中心是药物和农用化学发现中广受欢迎的部分。在这里,我们表明2-三氟甲基环氧乙烷的锂化-硼烷基化反应产生了高官能度和高度通用的三氟甲基取代的α-叔硼酸酯。中间硼酸酯配合物经历了具有完全保留立体特异性的碳基基团的1,2-重排,该过程仅在存在TESOTf的非极性溶剂中观察到。尽管三氟甲基不利地影响α-硼烷基的后续转化,但是Zweifel烯化反应提供了带有三氟甲基的季立体中心,并被烯烃,炔烃和酮取代。