Preparation of optically active n-butyl(methyl)phenyl-, tert-butyl(methyl)phenyl- and isopropyl(methyl)phenylsilanes from the corresponding silyl chlorides using 2,2′-dihydroxy-1,1′-binaphthyls as resolving agents
Enantiomeric silanes 4a, 4b and 4c were obtained from the corresponding racemic silyl chlorides via diastereomeric derivatives with (R)-[1,1′]binaphthalenyl-2,2′-diol; the optical purity of silanes 4a and 4c was determined (>98% ee) by HPLC using a chiral cyclodextrin-based column.
The present invention is a silylating method employing of formula (CH.sub.3)(R)(R.sup.1)SiX ; where R is an isopropyl group, R.sup.1 is a monovalent hydrocarbon group having 2 to 6 carbon atoms, and X is a chlorine atom or bromine atom. The silylating agent of the present invention provide silylation product which is much more stable than the silylation product obtained with trimethylchlorosilane, and its protective group is as stable as the silylation product obtained from t-butyldimethylchlorosilane. Moreover, the present described silylating agents are characterized by an easier desilylation than the t-butyldimethylsilyl group.
The present invention is a silylating agent of formula (CH.sub.3)(R)(R.sup.1)SiX; where R is an isopropyl group, R.sup.1 is a monovalent hydrocarbon group having 2 to 6 carbon atoms, and X is a chlorine atom or bromine atom. The silylating agent of the present invention provide silylation product which is much more stable than the silylation product obtained with trimethylchlorosilane, and its protective group is as stable as the silylation product obtained from t-butyldimethylchlorosilane. Moreover, the present described silylating agents are characterized by an easier desilylation than the t-butyldimethylsilyl group.
Cooperative Catalytic Activation of Si−H Bonds by a Polar Ru−S Bond: Regioselective Low-Temperature C−H Silylation of Indoles under Neutral Conditions by a Friedel−Crafts Mechanism
作者:Hendrik F. T. Klare、Martin Oestreich、Jun-ichi Ito、Hisao Nishiyama、Yasuhiro Ohki、Kazuyuki Tatsumi
DOI:10.1021/ja111483r
日期:2011.3.16
Merging cooperative Si-H bond activation and electrophilicaromaticsubstitution paves the way for C-3-selective indole C-H functionalization under electronic and not conventional steric control. The Si-H bond is heterolytically split by the Ru-S bond of a coordinatively unsaturated cationic ruthenium(II) complex, forming a sulfur-stabilized silicon electrophile. The Wheland intermediate of the subsequent