Question

in Wittig reaction intermediates formed are
a) Carbene b) Nitrene
d) Betain
Carbocation​

Answer 1

Answer:

(2+2) Cycloaddition of the ylide to the carbonyl forms a four-membered cyclic intermediate, an oxaphosphetane. Preliminary posultated mechanisms lead first to a betaine as a zwitterionic intermediate, which would then close to the oxaphosphetane.