ELECTRON-DEFICIENT CARBOCATIONS - DIRECT OBSERVATION OF ALPHA-CARBONYLMETHYL CATIONS BY LASER FLASH-PHOTOLYSIS

被引：39

作者：

JOHNSTON, LJ ^{[1
]}

KWONG, P ^{[1
]}

SHELEMAY, A ^{[1
]}

LEERUFF, E ^{[1
]}

机构：

[1] YORK UNIV,DEPT CHEM,N YORK M3J 1P3,ON,CANADA

来源：

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY | 1993年 / 115卷 / 05期

关键词：

D O I：

10.1021/ja00058a009

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

The 9-carbomethoxyfluoren-9-yl cation was generated under stable ion conditions and characterized by spectral data (visible/NMR spectroscopy) and product identification of the benzene and toluene trapping reactions. The laser flash excitation of methyl alpha-bromodiphenylacetate and methyl 9-bromo-9-fluorenylcarboxylate generated both the corresponding cations and radicals. Rate constants for nucleophilic quenching by alcohols and bromide ion were measured for both the alpha-carbomethoxy cations and the unsubstituted diphenylmethyl and 9-fluorenyl cations. The results indicated an increase in kinetic stability upon replacement of alpha-hydrogen by alpha-carbomethoxy. Direct comparison of quenching rate constants in the same solvent showed an increase in reactivity of the 9-fluorenyl cations relative to the diphenylmethyl cations.

引用

页码：1664 / 1669

页数：6

共 55 条

[1] SOLVOLYTIC REACTIVITY OF 1-TRIFLUOROMETHYL-1-PHENYLETHYL TOSYLATE - FORMATION OF A HIGHLY DESTABILIZED CARBONIUM-ION
ALLEN, AD
JANSEN, MP
KOSHY, KM
MANGRU, NN
TIDWELL, TT
[J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1982, 104 (01) : 207 - 211
[2] SOLVOLYSIS OF 1-ARYL-2,2,2-TRIFLUOROETHYL SULFONATES - KINETIC AND STEREOCHEMICAL EFFECTS IN THE GENERATION OF HIGHLY ELECTRON-DEFICIENT CARBOCATIONS
ALLEN, AD
AMBIDGE, IC
CHE, C
MICHAEL, H
MUIR, RJ
TIDWELL, TT
[J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1983, 105 (08) : 2343 - 2350
[3] LASER FLASH-PHOTOLYSIS STUDIES OF THE FORMATION AND REACTIVITIES OF PHENYL(NAPHTHYL)METHYL CARBOCATIONS GENERATED FROM PHOSPHONIUM SALT PRECURSORS
ALONSO, EO
JOHNSTON, LJ
SCAIANO, JC
TOSCANO, VG
[J]. CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE, 1992, 70 (06): : 1784 - 1794
[4] SOLVENT EFFECTS IN ORGANIC CHEMISTRY .3. SOLVATION OF STABLE CARBONIUM + AMMONIUM IONS IN WATER . TEMPERATURE COEFFICIENT OF HR ACIDITY SCALE
ARNETT, EM
BUSHICK, RD
[J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1964, 86 (08) : 1564 - &
[5] PHOTO-HETEROLYSIS AND PHOTO-HOMOLYSIS OF SUBSTITUTED DIPHENYLMETHYL HALIDES, ACETATES, AND PHENYL ETHERS IN ACETONITRILE - CHARACTERIZATION OF DIPHENYLMETHYL CATIONS AND RADICALS GENERATED BY 248-NM LASER FLASH-PHOTOLYSIS
BARTL, J
STEENKEN, S
MAYR, H
MCCLELLAND, RA
[J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1990, 112 (19) : 6918 - 6928
[6] BEGUE JP, 1980, ACCOUNTS CHEM RES, V13, P207, DOI 10.1021/ar50151a003
[7] Bergmann E, 1931, LIEBIGS ANN CHEM, V487, P225
[8] KINETIC HYDROGEN ISOTOPE EFFECTS IN INTERMOLECULAR HYDRIDE TRANSFER FROM ARYLALKANES TO 9-ARYLFLUOREN-9-YL CATIONS
BETHELL, D
HARE, GJ
KEARNEY, PA
[J]. JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2, 1981, (04): : 684 - 691
[9] KINETICS AND MECHANISM OF THE REACTION OF 9-ARYLFLUOREN-9-YL CATIONS WITH POLYMETHYLBENZENES IN TRIFLUOROACETIC-ACID SOLUTION
BETHELL, D
CLARE, PN
HARE, GJ
[J]. JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2, 1983, (12): : 1889 - 1893
[10] CHARPENT.M, 1974, B SOC CHIM FR II-CH, P343

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