Preparation, Properties, and Chemical Reactivity of α-Nitrosulfoximines, Chiral Analogues of α-Nitrosulfones

Abstract

Racemic N-methyl-S-(nitromethyl)-S-phenylsulfoximine (2) was prepared in 87% yield via alkaline nitration of N,S-dimethyl-S-phenylsulfoximine. Optically active N-methyl-S-(nitromethyl)-S-phenylsulfoximine (both enantiomers) was prepared in similar fashion. Reaction of racemic 2 with p-chlorophenyl isocyanate and a catalytic quantity of triethylamine in the presence of furan afforded dihydrofuroisoxazole 5, the product of nitrile oxide cycloaddition, in 42% yield (65:35 diastereomer ratio). Reaction of the dihydrofuroisoxazole 5 with phenyllithium and methyllithium afforded replacement of the sulfoximine group by phenyl and methyl, respectively. Reaction of racemic 2 with aromatic isocyanates and potassium carbonate afforded C-acylation products in 70-78% yield which existed as the ylide tautomers 9a,b. Methylation of racemic 2 afforded the C-alkylate N-methyl-S-(1-nitroethyl)-S-phenylsulfoximine (13), existing as the neutral tautomer.