Je. Baldwin et al., A NOVEL ENTRY TO CARBENOID SPECIES VIA BETA-KETOSULFOXONIUM YLIDES, Journal of the Chemical Society, Chemical Communications, (18), 1993, pp. 1434-1435
In the presence of suitable rhodium(II) catalysts, lactam derived beta
-ketosulfoxonium ylides can be transformed to beta-oxonitrogen heteroc
ycles, e.g. substituted 4-oxopyrrolidine, via intermediates of carbeno
id nature.