Laboratory of Asymmetric Catalysis and Synthesis, EPFL SB ISIC LCSA, BCH 4305, CH-1015 Lausanne (Switzerland) http://isic.epfl.ch/lcsa.
Angew Chem Int Ed Engl. 2014 Jan 7;53(2):507-11. doi: 10.1002/anie.201309207. Epub 2013 Dec 6.
Metal-catalyzed functionalizations at the ortho position of a directing group have become an efficient bond-forming strategy. A wide range of transformations that employ CpRh(III) catalysts have been described, but despite their synthetic potential, enantioselective variants that use chiral versions of the Cp ligand remain scarce (Cp*=pentamethyl cyclopentadienyl). Cyclopentadienyl compounds with an atropchiral biaryl backbone are shown to be suitable ligands for the efficient intramolecular enantioselective hydroarylation of aryl hydroxamates. Dihydrofurans that bear methyl-substituted quaternary stereocenters are thus obtained by CH functionalization under mild conditions.
金属催化的导向基团邻位官能团化已成为一种有效的成键策略。已经描述了广泛的采用 CpRh(III)催化剂的转化,但尽管它们具有合成潜力,但使用 Cp配体手性版本的对映选择性变体仍然很少(Cp*=五甲基环戊二烯基)。具有轴手性联芳基骨架的环戊二烯基化合物被证明是高效的分子内对映选择性氢芳基化芳基羟酰胺的合适配体。因此,在温和条件下通过 CH 官能化得到了带有甲基取代的季碳立体中心的二氢呋喃。