ANIONIC MIGRATION EFFECTED BY COLLISIONAL ACTIVATION - HYDRIDE ION MOBILITY IN KETO SUBSTITUTED ALKOXIDE ANIONS

Keto alcohols of the formula MeCO(CH2)(n)OH (n=3-5) are deprotonated b y HO- at both -OH or alpha to the carbonyl group. The various deproton ated species interconvert under the conditions of collisional activati on. The fragmentations of (M-H)(-) ions are varied and complex, with m ost fragmentations being directed from the alkoside centre. These frag mentations have been investigated by product ion and deuterium labelli ng studies. An interesting hydride transfer reaction occurs when n=3 a nd 4, i.e. H- transfer occurs from the CH2 group next to the alkoxide centre to the carbon of the carbonyl group to form (CH2CHO)-C-- as the product anion. This reaction does not occur when n=5. The correspondi ng Me(-) transfer from deprotonated MeCO(CH2)(n-1)C(Me)(2)OH (n=2 and 3) is not observed.