Asymmetric Synthesis of the Balanol Heterocycle via a Palladium-Mediated Epimerization and Olefin Metathesis
作者:Gregory R. Cook、P. Sathya Shanker、Scott L. Peterson
DOI:10.1021/ol990705+
日期:1999.8.1
utilizing a Pd-catalyzed equilibration of diastereomeric 5-vinyloxazolines to set the stereochemistry of the vicinal amino and hydroxyl groups. A ruthenium-catalyzed ring-closingmetathesis was employed to form the seven-membered nitrogenheterocyle.
The stereoselective synthesis of biologically important vinylglycine derivatives by reaction of homochiral 4-methoxycarbonyl-5-vinyloxazolidin-2-ones with organocopper reagents is described; 4,5-trans-oxazolidin-2-one 6 yields (E)-vinylglycines as the major products by treatment with the âhigher orderâ cyanocuprateâBF3 reagents or trialkylzincates in the presence of cuprous cyanide, 4,5-cis-oxazolidin-2-one 10 affords only the desired (E)-vinylglycines.