POLYMETHYLATED AND POLY(TERT)BUTYLATED DIPHENYLCARBENES - GENERATION,REACTIONS, KINETICS, AND DEUTERIUM-ISOTOPE EFFECTS OF STERICALLY CONGESTED TRIPLET CARBENES

Citation
H. Tomioka et al., POLYMETHYLATED AND POLY(TERT)BUTYLATED DIPHENYLCARBENES - GENERATION,REACTIONS, KINETICS, AND DEUTERIUM-ISOTOPE EFFECTS OF STERICALLY CONGESTED TRIPLET CARBENES, Journal of the American Chemical Society, 119(7), 1997, pp. 1582-1593
Citations number
93
Categorie Soggetti
Chemistry
ISSN journal
00027863
Volume
119
Issue
7
Year of publication
1997
Pages
1582 - 1593
Database
ISI
SICI code
0002-7863(1997)119:7<1582:PAPD-G>2.0.ZU;2-S
Abstract
Dimesitylcarbene (2a) was shown to decay by undergoing dimerization an d to have a half-life of 160 ms, some 5 orders of magnitude longer-liv ed than diphenylcarbene. Didurylcarbene (2b) was twice as long-lived a s 2a, while decamethyldiphenylcarbene (2c) decayed mainly unimolecular ly by abstracting Il from the o-methyl group and became shorter-lived than 2b. 2,4,6-Tri(tert-butyl)diphenylcarbene (14) decayed unimolecula rly almost exclusively by abstracting H from the o-tert-butyl group an d showed the lifetime of 125 mu s. The Arrhenius plot for H and D abst raction of 2c and 14 gave data consistent with a classical atom-transf er reaction, although the kinetic parameters are very different betwee n the two systems.