Gas-phase carbanion rearrangements. Does the Wittig rearrangement occur for deprotonated vinyl ethers?
Deprotonation of alkyl vinyl ethers (CH2CHOR) with NH2– in the gas phase yields the two carbanions CH2OR and –CHCHOR. The former ion can be synthesized specifically using the SN2(Si) reaction CH2C(SiMe3)OR + NH2–→CH2OR + Me3SiNH2: the ion undergoes several competitive and characteristic collision-induced reactions. For example, (i) when R Et, elimination of an alkene, i.e. CH2OR→(CH2CHO)–+(R–H), and (ii) the Wittig rearrangement CH2OR [graphic omitted] CH2C(R)O–.