ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The palladium-catalyzed reaction of iodobenzene, p-haloiodobenzenes (p-C6H4IX′; X′=F, Cl, Br, I) and p-dibromobenzene with 4-vinylcyclohexene (Heck arylation reaction of olefins) was investigated with Pd(OAc)2/PR3/Et3N (R=phenyl, o-tolyl) as a classical catalyst system and with Pd(OAc)2/KOAc/[BzEt3N]Cl in DMF as a phase-transfer catalyst system, respectively. Iodobenzene reacts with 4-vinylcyclohexene to give (E)-2-(cyclohex-3-enyl) vinylbenzene (1) as main product. p-Haloiodobenzenes react with 4-vinylcyclohexene to give (E)-p-halo-2-(cyclohex-3-enyl) vinylbenzene (3), p-halo-1-(cyclohex-3-enyl) vinylbenzene (4) or (E,E)-p-bis[2-(cyclohex-3-enyl)vinyl]benzene (5) depending on the reaction conditions and the catalyst system used. The phase-transfer catalyst system is less reactive but more selective. A reaction temperature of 80°C is necessary for reaction with p-dibromobenzene. The investigations demonstrate the much higher reactivity of the exocyclic double bond of 4-vincylcyclohexene in comparison with the endocyclic one.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19953370180
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