765-47-9Relevant articles and documents
Stereochemical Effects in the Gas-Phase Pinacol Rearrangement of cis- and trans-1,2-Dimethylcyclopentane-1,2-diol
Petris, Giulia de,Giacomello, Pierluigi,Picotti, Tito,Pizzabiocca, Adriano,Renzi, Gabriele,Speranza, Maurizio
, p. 7491 - 7495 (2007/10/02)
The pinacol rearrangement of cis- and trans-1,2-dimethylcyclopentane-1,2-diol, promoted by the gaseous Broensted acids D3+, CH5+/C2H5+, and t-C4H9+, was studied by mass spectrometric and radiolytic methods.Dehydration of the protonated substrate is rate limiting, and competitive experiments with pinacol, carried out at high pressure (760 torr), showed that the cis rearranges more rapidly than the trans isomer, indicating participation of the migrating methyl group to the leaving water molecule.The results are compared with those concerning the same substrates in solution, where no evidence of anchimeric assistance was found.
Oxidation by cobalt(III)acetate. Part 9. Effect of substituents on the oxidative Cleavage of glycols in acetic acid
Gunji, Tomokazu,Hirano, Masao,Morimoto, Takashi
, p. 1827 - 1832 (2007/10/02)
The kinetics of oxidative cleavage of glycols by obalt(III) acetate in acetic acid have been studied.The substrates examined include cis- and trans-cyclopentane- and cyclohexane-1,2-diols and their mono- and dimethyl derivatives.The rates were first-order in both cobalt(III)acetate and substrate in all cases.In the oxidation of five-membered ring diols, cis-diols were generally oxidized faster than the trans-isomers.Complex results were obtained in the case of six-membered ring diols.Thermodynamic parameters were calculated for all the substrates.A mechanism involving a bidente complex of cobalt(III) acetate dimer and glycol is sugge sted, except for the case of trans-cyclopentane-1,2-diols, for which a monodentate intermediate is proposed.
A SYNTHESIS OF GYMNOMITROL
Buechi, George,Chu, Ping-Sun
, p. 4509 - 4514 (2007/10/02)
Condensation of 1,2-dimethylcyclopentene 10 with 2-methyl-4,4,5-trimethoxycyclohexa-2,5-dienone 7 in methylene chloride-nitromethane with added stannic chloride gave a mixture of the two diastereomeric bicyclooctanes 13 and 14 by ionic cycloaddition.After selective reduction of the saturated carbonyl group with sodium borohydride, and hydrogenation of the double bond the two epimers 18 and 20 (ratio 3.3:1) were separable by chromatography.Protection of the hydroxy group in 18 with dihydropyran and, reduction of the α-methoxyketone 19 with calcium in liquid ammonia gave ketone 21.Gymnomitrol 1 was then prepared by Wittig olefination followed by deprotection of the hydroxy group.