O-Substituted N-oxy arylsulfinamides and sulfonamides in Michael reactions

O-Substituted N-oxy arylsulfinamides and sulfonamides undergo fast aza-Michael reaction in the presence of base and electron-deficient alpha,beta-unsaturated olefins under mild conditions. With N-silyloxy benzenesulfinamides, no aza-Michael product is observed and a hetero aza-Brook type rearrangement takes place induced by the base. Room temperature N-desulfinylation of N-benzyloxybenzenesulfinamide is achieved using BF(3)center dot Et(2)O. N-Alkoxy arylsulfonamides aza-Michael adducts are found to be generally highly stable under strongly acidic and basic conditions.