Catalytic Asymmetric Intramolecular Aminopalladation: Enantioselective Synthesis of Vinyl-Substituted 2-Oxazolidinones, 2-Imidazolidinones, and 2-Pyrrolidinones
作者:Larry E. Overman、Travis P. Remarchuk
DOI:10.1021/ja017198n
日期:2002.1.1
A new catalytic asymmetric synthesis of five-membered nitrogen heterocycles is reported. This synthesis employs ferrocenyloxazoline palladacycles (FOP trifluoroacetate catalysts) 2 and 4 and proceeds by a catalytic cycle involving Pd(II) intermediates. For example, prochiral (Z)-4-acetoxy-2-buten-1-ols are condensed with an arylsulfonyl isocyanate and the derived allylic N-arylsulfonylcarbamates cyclize
Palladium(II)-Catalyzed Highly Regio- and Diastereoselective Cyclization of Difunctional Allylic <i>N</i>-Tosylcarbamates. A Convenient Synthesis of Optically Active 4-Vinyl-2-oxazolidinones and Total Synthesis of 1,4-Dideoxy-1,4-imino-<scp>l</scp>-xylitol
作者:Aiwen Lei、Guosheng Liu、Xiyan Lu
DOI:10.1021/jo0161429
日期:2002.2.1
A Pd(II)-catalyzed cyclization of difunctional allylic N-tosyl carbamates in the presence of halide ions was developed with high regio- and diastereoselectivity. The reaction involves aminopalladation of alkene and beta-heteroatom elimination to regenerate Pd(II) species. When the readily available homochiral alcohols were used as substrates, highly opticallyactive 4-vinyl-2-oxazolidinones were easily