Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan.
Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
Science. 2020 Aug 21;369(6506):970-974. doi: 10.1126/science.abc8320.
Site selectivity and stereocontrol remain major challenges in C-H bond functionalization chemistry, especially in linear aliphatic saturated hydrocarbon scaffolds. We report the highly enantioselective and site-selective catalytic borylation of remote C(sp)-H bonds γ to the carbonyl group in aliphatic secondary and tertiary amides and esters. A chiral C-H activation catalyst was modularly assembled from an iridium center, a chiral monophosphite ligand, an achiral urea-pyridine receptor ligand, and pinacolatoboryl groups. Quantum chemical calculations support an enzyme-like structural cavity formed by the catalyst components, which bind the substrate through multiple noncovalent interactions. Versatile synthetic utility of the enantioenriched γ-borylcarboxylic acid derivatives was demonstrated.
在 C-H 键功能化化学中,特别是在直链脂肪族饱和烃骨架中,位点选择性和立体选择性仍然是主要挑战。我们报告了在脂肪族仲胺和叔酰胺及酯中羰基γ位的远程 C(sp)-H 键的高对映选择性和位点选择性催化硼酸化。手性 C-H 活化催化剂是由铱中心、手性单膦配体、非手性脲-吡啶受体配体和频哪醇硼酸酯基团模块化组装而成的。量子化学计算支持由催化剂组成部分形成的类似酶的结构腔,该结构腔通过多种非共价相互作用结合底物。对映富集的γ-硼酸基羧酸衍生物的多功能合成实用性得到了证明。