Journal of the Chemical Society. Perkin transactions II p. 1273 - 1280 (1987)
Update date:2022-08-04
Topics:
Earl, Harold A.
Stirling, Charles J. M.
Eliminative fission of cyclobutanes has been compared with that of analogous cyclopropanes; reactivity differences of 103.7-104.8 have been determined.In both sets of compounds, mechanisms have been shown to involve rate-determining ring fission.The possibilities that the large reactivity differences between the comparably strained systems are due either to peculiarity in the cyclobutane structures or to their abnormally slow deprotonation are rejected.Analysis of strain in the two systems suggests that as ring fission occurs, dispersal of the excess of enthalpy of the cyclobutanes is a less sensitive function of extension of a bond in the ring than for the cyclopropanes.The behaviour of these systems is compared with cleavage of cyclopropanes and cyclobutanes in other reactions; the results are remarkably similar.Calculations using the MINDO3 programme have been carried out for eliminative fissions of cyclopropylmethyl and cyclobutylmethyl carbanions.These reproduce remarkably closely the difference between the heats of formation of the species at the energy maxima for fission of each ring size; the maximum for fission of the cyclobutane is considerably displaced along the reaction co-ordinate towards product.
View MoreContact:+65 9658 0999
Address:26 Sin Ming Lane, Midview City, #05-118, Singapore 573971
Ceresking Ecology & Technology co.,ltd
Contact:86 22 66218397
Address:Room 1613, Zheshang Mansion, No. 1988, Yingbin Avenue, Binhai New District, Tianjin,China.
KINHENG CHEMICAL(SHANGHAI)CO., LTD.
Contact:+8621-60490170
Address:Room401, No.28,Lane 189, Yangshupu Rd. Shanghai, China.
Henan Yellow River New Material Technology Co.Ltd.
website:http://www.yellowriverchem.com
Contact:0086-373-7278760
Address:Chengguan Town, Yuanyang County
Contact:+44 (0)161 367 9441
Address:
Doi:10.1002/cbdv.200900039
(2009)Doi:10.1016/S0040-4039(00)80432-3
(1988)Doi:10.1016/j.tetlet.2009.08.102
(2009)Doi:10.1007/BF00962768
(1988)Doi:10.1016/j.bmcl.2014.05.069
(2014)Doi:10.1021/jo902254w
(2009)
