Lewis Acid Catalyzed Intramolecular Allylic Substitution of Bis(trichloroacetimidates): A Versatile Approach to Racemic Unsaturated Amino Acids
作者:Liene Grigorjeva、Aigars Jirgensons
DOI:10.1002/ejoc.201100060
日期:2011.5
Lewis acid catalyzed cyclization of trichloroacetimidates derived from 1,4-butenediols and 1,5-butenediols was achieved to give 4-vinyl oxazolines and 4-vinyloxazines in good to excellent yields. The cyclization products were transformed to protected unsaturated α- and β-amino acids, thus demonstrating the novel approach to access these important classes of compounds.
A Diastereoselective Intermolecular Heck Reaction of 1,3-Dioxepins
作者:Christopher G. Nasveschuk、Jeffrey D. Frein、Nathan T. Jui、Tomislav Rovis
DOI:10.1021/ol702294u
日期:2007.11.1
A highly diastereoselective intermolecularHeckreaction of 1,3-dioxepins is reported. Substitution at both the 2- and 4-positions of the dioxepin directs the Pd coordination and subsequent olefin insertion to provide the trans-disubstituted adduct in good yield and high diastereoselectivity. Chemoselective Heckreaction occurs at the dioxepin alkene in the presence of other olefinic functional groups
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
Epoxidation and cyclopropanation of 2-silyl-3-alkenols. A study of 1,2-asymmetric induction
作者:Yannick Landais、Liliana Parra-Rapado
DOI:10.1016/0040-4039(95)02386-0
日期:1996.2
Epoxidation and cyclopropanation of 2-silyl-3-alkenols have been shown to occur with high 1,2-stereocontrol through substrate directable reactions. Both syn and anti epoxides are thus available from E and Z-allylsilanes. This contrasts with the results usually observed for allylsilanes lacking a coordinating group.