S-Ethenylsulfoximine Derivatives. Reagents for Ethylenation of Protic Nucleophiles

Article abstract of DOI:10.1021/jo01290a012

The preparation of S-vinyl and S-(2-substituted)ethenyl derivatives of sulfoximines is described.Vinyl-, (2-phenylethenyl)-, (2,2-diphenylethenyl)-, (2-methyl-1-propenyl)-, <2-(p-tolyl)ethenyl)-, and <2-(2-furanyl)ethenyl>(dimethylamino)phenyloxosulfonium fluoroborates were found to undergo an addition-elimination reaction sequence with protic nitrogen and carbon nucleophiles, resulting in ethylenation of the nucleophile and N,N-dimethylbenzenesulfinamide.Primary amines gave aziridines, enamines gave cyclopropyl derivatives of iminium salts or pyrrolidinium salts, anions of active methylene compounds gave dihydrofurans and/or cyclopropanes, and anions of nitroalkanes gave cyclic nitronic esters and/or nitrocyclopropanes.In several cases vinyl salts were generated in situ from β-methoxyoxosulfonium salts.Treatment of (-)-(S)-dimethylamino)phenyl(trans-2-phenylethenyl)oxosulfonium fluoroborate with methyl cyanoacetate in methanol containing sodium methoxide gave, in 81percent yield, (+)-(1S,2R)-methyl 1-cyano-2-phenylcyclopropanecarboxylate of 25.5percent optical purity.The same salt upon treatment with methyl nitroacetate gave, in 95percent yield, methyl 4-phenyl-3-isoxazolinecarboxylate 2-oxide with 33percent enantiomeric excess.Cyclopropanes were formed upon treatment of S-methyl-S-(trans-2-phenylethenyl)-N-(p-tolylsulfonyl)sulfoximine with anions of active methylene compounds.