821-07-8Relevant articles and documents
Pyrolysis of tricyclic cyclobutane-fused sulfolanes as a route to cis-1,2-divinyl compounds and their Cope-derived products
Aitken, R. Alan,Cadogan, J. I. G.,Gosney, Ian,Humphries, Caroline M.,McLaughlin, Leo M.,Wyse, Stuart J.
, p. 605 - 614 (2007/10/03)
Functionalisation of the double bond of 3-thiabicyclohept-6-ene 3, readily formed by hydrolysis of the cycloadduct 1 of 3-sulfolene and maleic anhydride followed by oxidative bis-decarboxylation, gives tricyclic sulfones 5-7 and 9 with the bicyclo2,4> skeleton. FVP of 3 results in stereospecific extrusion of SO2 to give Z-hexa-1,3,5-triene which undergoes electrocylisation to give cyclohexa-1,3-diene while reaction of 3 with LiAlH4 results in non-stereospecific extrusion to give Z- and E-hexa-1,3,5-triene. Upon FVP the tricyclic sulfones 5-7 and 9 lose SO2 to give 7-membered ring products 16-19 by Cope rearrangement of the initially formed cis-1,2-divinyl intermediates 15. The 1,3-dipolar cycloaddition of nitrile oxides and a nitrone to the double bond of 3 gives tricyclic sulfones with the tricyclo2,6> skeleton and a wider variety of these can be prepared by conventional reactions of 1. Upon FVP these lose SO2 to give stable cis-1,2-divinyl compounds 23, 24, 37-40 and 41-44. The Diels-Alder adducts 48 and 49 have been prepared from 3 and these behave differently upon FVP, losing SO2 and butadiene to give tetrasubstituted benzenes, in the latter case by way of an unexpected tetracyclic intermediate.
Central and Lateral Bicyclo[1.1.0]butane Bond Cleavage with Subsequent Wagner-Meerwein Rearrangements or Carbene Formation in the 185-nm Photolysis of Tricyclo[3.1.0.02,6]hexane, Tricyclo[4.1.0.02,7]heptane, and Tricyclo[5.1.0.02,8]octane
Adam, Waldemar,Alt, Christine,Braun, Max,Denninger, Uwe,Zang, Gerald
, p. 4563 - 4571 (2007/10/02)
The 185-nm photochemistry of tricyclop[3.1.0.02,6]hexane, tricyclo[4.1.0.02,7] heptane, [1,7-d2]tricyclo[4.1.0.02,7]heptane, tricyclo[5.1.0.02,8]octane, and [1-d]tricyclo[5.1.0.02,8]octane was investigated. Tricyclo[5.1.0.02,8]octane yields bicyclo[4.2.0]oct-7-ene, tricyclo[4.1.0.02,7]heptane yields 85% bicyclo[3.2.0]hept-6-ene and 15% 3-methylenecyclohexene, and tricyclo[3.1.0.02,6]hexane yields 39% 3-methylenecyclopentene, 15% 1,3-cyclohexadiene, 26% trans-1,3,5-hexatriene, and 20% cis-1,3,5-hexatriene. From the deuterium-labeling studies, it is concluded that, in the case of the tricyclooctane, the central bicyclobutane bonds cleave in the primary step to give radical cationic or zwitterionic species that undergo a Wagner-Meerwein rearrangement. Also, in the case of tricycloheptane, this is the dominating pathway but lateral C-C bond cleavage with subsequent carbene and product formation takes place to the extent of ca. 15%. For tricyclohexane, this pathway becomes the major route. Our photomechanistic observations are in good agreement with earlier theoretical investigations on the relative energetic ordering of the bicyclobutane HOMOs, in that the product composition reflects this.
THE THERMAL REARRANGEMENT OF CIS,CIS-1-FLUORO-2-METHYL-3-VINYLCYLOPROPANE. THE KINETIC EFFECT OF A SINGLE FLUORINE SUBSTITUENT
Elsheimer, Seth,Dolbier, William R.
, p. 119 - 128 (2007/10/02)
It was demonstrated through a kinetic study of the thermal rearrangement of cis,cis-1-fluoro-2-methyl-3-vinylcyclopropane to cis-3-fluoro-1,4-hexadiene that a single fluorine substituent lowers that activation barrier for rearrangement by about 2 kcal/mole as compared to 6.4 kcal/mole for geminal difluoro substitution.
