A. Flamini, A. Giuliani
Nov 1, 1983
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Journal
Journal of Molecular Catalysis
Abstract
Abstract Dipotassium hexahalogeno-osmates, K 2 OsX 6 (X = Cl, Br) dissolved in non-aqueous inert organic solvents (benzene, o -dichlorobenzene, bromo-benzene) by addition of dicyclohexyl-18-crown-6 ether (C 20 H 36 O 6 ) are catalytic precursors for the multiple double bond shift in olefins. Studies on the interaction between K 2 OgX 6 and several olefins (1-heptene, 1-heptene-3d 2 , 1-pentene, cis -stilbene, 3,3-dimethyl-l-butene) support an osmium hydride species, probably [OsHX 5 ] = , as the true catalyst, which affords the olefin isomerization through successive 1,2-addition-elimination steps to the CC double bond. Such an alleged osmium hydride species is formed by allylic hydrogen atom abstraction from the olefin with formation of the corresponding conjugate diolefin.