[reaction: see text] tert-Butyl (phenylsulfonyl)alkyl-N-hydroxycarbamates 1 have been easily prepared from aldehydes and tert-butyl N-hydroxycarbamate in a methanol-water mixture using sodium benzenesulfinate and formic acid. These sulfones 1 behave as N-(Boc)-protected nitrones 4 in the reaction with organometallics to give N-(Boc)hydroxylamines. Some chemical transformations showing their interest
Platinum-catalyzed cyclizations viacarbene intermediates: syntheses of complementary positional isomers of isoxazoles
作者:Paul A. Allegretti、Eric M. Ferreira
DOI:10.1039/c2sc21671j
日期:——
A novelsynthesis of regioisomeric isoxazoles is described. Using catalytic platinum, both propargylic N-hydroxycarbamates and N-alkoxycarbonyl amino ethers can be cyclized to form differentially substituted isoxazoles. Reaction conditions are developed that address specific aspects of the catalytic manifold. A unique mechanism involving a Pt-carbene intermediate is proposed, and deuterium labeling