X=Y-ZH SYSTEMS AS POTENTIAL 1,3-DIPOLES.PART 18.CYCLOADDITION OF 4Π-SULPHINYLAMINOMETHAMIDE SPECIES GENERATED FROM α-AMINO ACIDS AND α-AMINO ACID ESTERS BY SULPHONYL GROUP TRANSFER.X-RAY CRYSTAL STRUCTURE OF 4-ISO-PROPYL-7-METHYL-2-THIA-6,8-DIOXO-3,7-DIAZOBICYCLOOCTANE S-OXIDE.

Article abstract of DOI:10.1016/S0040-4020(01)86198-6

Sulphonyl group transfer from N-sulphonyl aniline to α-amino acids followed by dacarboxylation affords 4Π-sulphinylaminomethamide species with an anti-configuration stereospecifically.Analogous reactions with α-amino acid esters occur at room temperature in toluene and afford carbomethoxy substituted 4Π-sulphinylaminomethamide species non-stereoselectively.Both types of 4Π-species are trapped in good yield in <3+2>-cycloaddition reactions by N-methylmaleimide.The mechanism of the reactions are discussed and evidence presented in favour of a 4Π-anionic species for the reactions involving α-amino acid esters.A novel cyclic intermediate is invoked to account for the stereospecific formation of anti-4Π-sulphinylaminomethamide species from α-amino acids.These latter processes also probably involve 4Π-anionic species.