The pinacol rearrangement of cis- and trans- 1,2-dimethylcycIopentane-1 ,2-diol, promoted by the gaseous Brernsted acids D3+,C H5+/C2H5+a,n d t-C4H9+w, as studied by mass spectrometric and radiolytic methods. Dehydration of the protonated substate 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.
Stereochemical effects in the gas-phase pinacol rearrangement of cis- and trans-1,2-dimethylcyclopentane-1,2-diol / DE PETRIS, Giulia; Giacomello, Pierluigi; T., Picotti; A., Pizzabiocca; G., Renzi; Speranza, Maurizio. - In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - ISSN 0002-7863. - STAMPA. - 108:24(1986), pp. 7491-7495. [10.1021/ja00284a009]
Stereochemical effects in the gas-phase pinacol rearrangement of cis- and trans-1,2-dimethylcyclopentane-1,2-diol
DE PETRIS, GIULIA;GIACOMELLO, Pierluigi;SPERANZA, Maurizio
1986
Abstract
The pinacol rearrangement of cis- and trans- 1,2-dimethylcycIopentane-1 ,2-diol, promoted by the gaseous Brernsted acids D3+,C H5+/C2H5+a,n d t-C4H9+w, as studied by mass spectrometric and radiolytic methods. Dehydration of the protonated substate 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
