Asymmetric α-2-tosylvinylation of in situ-generated N-2-tosylvinyl proline-derived ammonium ylides
Asymmetric α-2-tosylvinylation of N-substituted proline esters using ethynyl tolyl sulfone as an electrophile was shown to proceed in good yield with high enantioselectivities without the addition of any bases. The reaction proceeds via the formation of N-2-tosylvinyl ammonium ylides.