GENERATION OF ALKYL CARBANIONS IN THE GAS-PHASE

被引:86
作者
GRAUL, ST [1 ]
SQUIRES, RR [1 ]
机构
[1] PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907
关键词
D O I
10.1021/ja00163a006
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The scope and limitations of collision-induced decarboxylation of carboxylate negative ions as a method for generating gas-phase carbanions are described. Simple alkyl carbanions can be observed as fragments from a variety of aliphatic carboxylates, provided only that the carbanion has a lifetime toward electron detachment greater than ~25 µs. Several heretofore unknown alkyl carbanions have been observed, including the neopentyl anion, the 2- and 3-methylbutyl anions, cyclopentylmethyl anion, and cyclohexylmethyl anion, as well as cyclic and polycyclic carbanions such as the 1- and 2-methylcyclopropyl anions and the 1-bicyclopentyl anion. An empirical correlation between the electron affinities of primary alkyl radicals (RCH2) and the analogous alkoxyl radicals (RO) is described that correctly predicts the stability and detectability of the corresponding primary carbanion fragments (RCH2)- from collision-induced decarboxylation. A number of α-substituted methyl anions and β-substituted ethyl anions have been formed by this method; both familiar and novel examples of these types of carbanions are descr;ibed. The competing higher energy fragmentations and low-energy reactions of collisionally activated carboxylate ions are also discussed, including β-radical cleavages, remote-site fragmentations, and intramolecular isomerizations that occur prior to dissociation. © 1990, American Chemical Society. All rights reserved.
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页码:2506 / 2516
页数:11
相关论文
共 100 条
[1]  
ADAMS J, 1987, Spectroscopy (Amsterdam), V5, P199
[2]  
ADAMS J, 1989, J AM CHEM SOC, V111, P4315
[3]   VINYL ANION SYNTHESIS IN THE GAS-PHASE [J].
ANDERSON, KK ;
KASS, SR .
TETRAHEDRON LETTERS, 1989, 30 (23) :3045-3048
[4]   THEORETICAL-STUDY OF ALPHA-LACTONE, ACETOXYL DIRADICAL, AND THE GAS-PHASE DISSOCIATION OF THE CHLOROACETATE ANION [J].
ANTOLOVIC, D ;
SHINER, VJ ;
DAVIDSON, ER .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1988, 110 (05) :1375-1381
[5]  
Aurelle H., 1987, RAPID COMMUN MASS SP, V1, P65
[6]   THE EVALUATION OF MOLECULAR ELECTRON-AFFINITIES [J].
BAKER, J ;
NOBES, RH ;
RADOM, L .
JOURNAL OF COMPUTATIONAL CHEMISTRY, 1986, 7 (03) :349-358
[7]  
Bartmess J.E., 1979, J AM CHEM SOC, V101, P6047
[8]   GAS-PHASE ACIDITY OF ALIPHATIC-ALCOHOLS [J].
BOAND, G ;
HOURIET, R ;
GAUMANN, T .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1983, 105 (08) :2203-2206
[9]   ACIDITY ORDER OF SELECTED BRONSTED ACIDS IN GAS-PHASE AT 300 DEGREES K [J].
BOHME, DK ;
YOUNG, LB ;
LEERUFF, E .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1972, 94 (15) :5153-&