ISSN:
0009-2940
Keywords:
Cyclopropenes, 3,3-dimethyl-1-trimethylsilyl-substituted
;
Cyclopropene, isomerisation
;
Gas-phase kinetics
;
Ring opening
;
Diradical intermediates
;
Cyclopropylidene intermediates
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The gas-phase pyrolyses of 1,3,3-trimethyl-2-(trimethylsilyl)-cyclopropene (9), 3,3-dimethyl-1,2-bis(trimethylsilyl)cyclopropeneTextReactantlog (A/s-1)Ea/kj mol-1(kcal mol-1)913.41 ± 0.22192.1 ± 2.5(45.9 ± 0.6)1013.54 ± 0.19184.4 ± 2.1(44.1 ± 0.5)1112.17 ± 0.38124.6 ± 3.1(29.8 ± 0.7)(10), and 3,3-dimethyl-1-(methylthio)-2-(trimethylsilyl)cyclopropene (11) have been studied, and the pressure-independent Arrhenius parameters listed in the table were obtained. All three rearrangements are homogeneous, first-order and unimolecular reactions. Rather surprisingly all reactions give the corresponding isomeric allenes as the main products. Amongst possible mechanisms discussed, 10 is proposed to react via a cyclopropylidene intermediate, whilst the results for 9 and 11 throw light on the relative importance of the diradical- and vinylcarbene-type intermediates produced by cyclopropene ring opening.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19941270134
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