Department of Chemistry, University of California , Berkeley, California 94720, United States.
J Am Chem Soc. 2017 Sep 6;139(35):12137-12140. doi: 10.1021/jacs.7b06679. Epub 2017 Aug 25.
We report highly enantioselective intramolecular, silylations of unactivated, primary C(sp)-H bonds. The reactions form dihydrobenzosiloles in high yields with excellent enantioselectivities by functionalization of enantiotopic methyl groups under mild conditions. The reaction is catalyzed by an iridium complex generated from [Ir(COD)OMe] and chiral dinitrogen ligands that we recently disclosed. The C-Si bonds in the enantioenriched dihydrobenzosiloles were further transformed to C-Cl, C-Br, C-I, and C-O bonds in final products. The potential of this reaction was illustrated by sequential C(sp)-H and C(sp)-H silylations and functionalizations, as well as diastereoselective C-H silylations of a chiral, natural-product derivative containing multiple types of C-H bonds. Preliminary mechanistic studies suggest that C-H cleavage is the rate-determining step.
我们报告了一种高度对映选择性的未活化的、伯 C(sp)-H 键的分子内硅烷化反应。该反应通过在温和条件下对非对映甲基官能化，以高产率和优异的对映选择性形成二氢苯并硅杂环戊烯。该反应由[Ir(COD)OMe]和我们最近披露的手性二氮配体生成的铱配合物催化。在对映富集的二氢苯并硅杂环戊烯中，C-Si 键进一步转化为最终产物中的 C-Cl、C-Br、C-I 和 C-O 键。通过连续的 C(sp)-H 和 C(sp)-H 硅烷化以及官能化，以及含有多种 C-H 键的手性天然产物衍生物的非对映选择性 C-H 硅烷化反应，说明了该反应的潜力。初步的机理研究表明，C-H 断裂是速率决定步骤。
