Synthesis of Enantioenriched Allylic Silanes via Nickel-Catalyzed Reductive Cross-Coupling
作者:Julie L. Hofstra、Alan H. Cherney、Ciara M. Ordner、Sarah E. Reisman
DOI:10.1021/jacs.7b11707
日期:2018.1.10
asymmetric Ni-catalyzed reductive cross-coupling has been developed to prepare enantioenriched allylic silanes. This enantioselective reductive alkenylation proceeds under mild conditions and exhibits good functional group tolerance. The chiral allylic silanes prepared here undergo a variety of stereospecific transformations, including intramolecular Hosomi-Sakurai reactions, to set vicinal stereogenic centers
已开发出不对称 Ni 催化的还原交叉偶联来制备对映体富集的烯丙基硅烷。这种对映选择性还原烯基化在温和条件下进行,并表现出良好的官能团耐受性。这里制备的手性烯丙基硅烷经过各种立体定向转化,包括分子内细美-樱井反应,以设置具有优异手性转移的邻位立体中心。
Hauser; Hance, Journal of the American Chemical Society, 1952, vol. 74, p. 5091,5094,5095
Mechanical activation of magnesium turnings for the preparation of reactive Grignard reagents
作者:Karen V. Baker、John M. Brown、Nigel Hughes、A. Jerome Skarnulis、Ann Sexton
DOI:10.1021/jo00002a039
日期:1991.1
Preactivation of magnesium by dry stirring in an inert atmosphere is highly beneficial for the clean synthesis of reactive allylic or benzylic organomagnesium chlorides. This procedure routinely produces 0.4 M solutions of the Grignard reagent in diethyl ether free from coupling products. The purity may be directly assayed by C-13 NMR spectroscopy. Using spin saturation transfer techniques, the rate constant for interconversion of the enantiomers of (1-phenyl-2-methylpropyl)magnesium chloride in Et2O at 25-degrees-C was shown to be < 0.2s-1. Electron microscopy has been used to define the surface changes occurring e during the dry stirring of magnesium turnings.