A series of enantiomerically pure mono- and bis-aryl tert-butyl sulfoxides were synthesised to promote the enantioselective allylation of aldehydes with allyltrichlorosilane. Moderate to good yields and modest to high enantioselectivities were achieved. The absence of nonlinear effect, spacer effect, promoter loading and concentration effect indicate that only one molecule of aryl tert-butyl sulfoxide is involved in the stereodetermining step.
A reaction of Grignard reagents with an optically pure N-sulfinylimine derived from methyl 2-formylbenzoate yields enantioenriched isoindolinones and tert-butyl sulfoxides. The products are formed by the addition of the nucleophile to N-sulfinylimine followed by cyclization to form N-tert-butylsulfinylisoindolinone, which readily undergoes substitution with a second equivalent of Grignard reagent.
tert-Butanesulfinylthioether ligands: synthesis and application in palladium-catalyzed asymmetric allylic alkylation
作者:Jibing Liu、Guihua Chen、Junwei Xing、Jian Liao
DOI:10.1016/j.tetasy.2011.02.031
日期:2011.3
the tert-butylsulfinyl moiety as the sole chiral source were designed and synthesized through a simple and efficient pathway. These ligands are effective catalyst precursors for the palladium-catalyzedallylicalkylation of 1,3-diphenyl-2-propenyl acetate and moderate to good stereoselectivities (up to 84% ee) were obtained.