94922-19-7Relevant academic research and scientific papers
THE REGIOSELECTIVITY OF RHODIUM AND PALLADIUM-CATALYSED CYCLISATIONS OF 2-BROMO-1,6- AND 1,7-DIENES
Grigg, Ronald,Stevenson, Paul,Worakun, Tanachat
, p. 2033 - 2048 (2007/10/02)
2-bromo-1,6-dienes are catalytically cyclised to a mixture of the corresponding 3,4-bis(methylene)cyclopentane and 5-methylenecyclohex-3-ene.Wilkinson's catalyst shows good selectivity for the 5-membered ring product whilst palladium catalysts, in general, show little selectivity.Addition of tetraethylammonium salts, especially the chloride, allow the palladium catalysed reactions to be carried out at 30 deg C in good yield and with high selectivity for the 5-membered ring. 2-Bromo-1,7-dienes are cyclised regiospecifically to 6-membered rings by the same catalysts although some double bond isomerisation also occurs.The mechanism of the catalytic cyclisations is discussed.The 3,4-bis(methylene) cyclopentanes undergo facile Diels-Alder reactions.
