Gas-phase carbanion rearrangements. Does the Wittig rearrangement occur for deprotonated vinyl ethers?
Abstract
Deprotonation of alkyl vinyl ethers (CH2CHOR) with NH2– in the gas phase yields the two carbanions CH2
OR and –CH
CHOR. The former ion can be synthesized specifically using the SN2(Si) reaction CH2
C(SiMe3)OR + NH2–→CH2
OR + Me3SiNH2: the ion undergoes several competitive and characteristic collision-induced reactions. For example, (i) when R
Et, elimination of an alkene, i.e. CH2
OR→(CH2CHO)–+(R–H), and (ii) the Wittig rearrangement CH2
OR [graphic omitted] CH2
C(R)O–.