Organocatalytic Asymmetric Synthesis of Chiral Dioxazinanes and Dioxazepanes with in Situ Generated Nitrones via a Tandem Reaction Pathway Using a Cooperative Cation Binding Catalyst
Heterocyclic skeletons play major roles in pharmaceuticals and biological processes. Cycloaddition reactions are most suitable synthetic tools to efficiently construct chemically diverse sets of heterocycles with great structural complexity owing to the s
Reactions of in situ generated N-Boc nitrones with aromatic and heteroaromatic Grignard reagents: Application to the synthesis of zileuton
(Chemical Equation Presented) A new class of α-aromatic-N- hydroxylamines has been prepared by reaction of tert-butyl (phenylsulfonyl) alkyl-N-hydroxycarbamates with aromatic and heteroaromatic Grignard reagents. Reactions proceed via a base-assisted elimination of the phenylsulfonyl group leading to N-Boc nitrones. This methodology has been applied to the synthesis of zileuton.
Guinchard, Xavier,Denis, Jean-Noel
p. 2028 - 2031
(2008/09/19)
tert-butyl (phenylsulfonyl)alkyl-N-hydroxycarbamates: The first class of N-(Boc) nitrone equivalents
(Chemical Equation Presented) 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 as building blocks in organic synthesis are described.