Other sulfonium varieties are seen in the Swern oxidation and the Stevens rearrangement.  
Similar activity to these compounds is seen in the transition metal- containing Schrock carbenes, while condensation of an amino acid and an aldehyde can produce azomethine examples.  The (*) Corey-Chaykovsky reagent is an example of these which may be prepared by reacting DMSO and methyl iodide in the presence of a strong base, and it may be used to convert a carbonyl to an epoxide.  Other sulfonium varieties are seen in the Swern oxidation and the Stevens rearrangement.  Also used in a phosphonium form to convert carbonyls to alkenes in the Wittig reaction, for 10 points, name these chemical species with adjacent atoms bearing positive and negative charges.
Similar activity to these compounds is seen in the transition metal- containing Schrock carbenes, while condensation of an amino acid and an aldehyde can produce azomethine examples.  
{ylide}s (4) [AU]