We report an unprecedented mode of reactivity of carboxylic acids. A series of tertiary carboxylic acids, containing at least one phenyl α-substituent, undergo loss of carbon monoxide at room temperature (295 K), by a one pot reaction with 0.5-1 molar equivalents of WCl 6 in dichloromethane. A plausible mechanism for the Ph 3 CCO 2 H/WCl 6 reaction, leading to [CPh 3 ][WOCl 5 ] and Ph 3 CCl, is proposed on the basis of DFT calculations. The analogous reactions involving CEt(Ph) 2 CO 2 H, CMe(Ph) 2 CO 2 H and CMe 2 (Ph)CO 2 H selectively afforded stable hydrocarbons (alkene or indene, depending on the case), apparently resulting from the rearrangement of elusive tertiary carbocations.
Bartalucci N., Bortoluzzi M., Zacchini S., Pampaloni G., Marchetti F. (2019). Straightforward formation of carbocations from tertiary carboxylic acids: Via CO release at room temperature. DALTON TRANSACTIONS, 48(5), 1574-1577 [10.1039/c8dt04416c].
Straightforward formation of carbocations from tertiary carboxylic acids: Via CO release at room temperature
Zacchini S.;
2019
Abstract
We report an unprecedented mode of reactivity of carboxylic acids. A series of tertiary carboxylic acids, containing at least one phenyl α-substituent, undergo loss of carbon monoxide at room temperature (295 K), by a one pot reaction with 0.5-1 molar equivalents of WCl 6 in dichloromethane. A plausible mechanism for the Ph 3 CCO 2 H/WCl 6 reaction, leading to [CPh 3 ][WOCl 5 ] and Ph 3 CCl, is proposed on the basis of DFT calculations. The analogous reactions involving CEt(Ph) 2 CO 2 H, CMe(Ph) 2 CO 2 H and CMe 2 (Ph)CO 2 H selectively afforded stable hydrocarbons (alkene or indene, depending on the case), apparently resulting from the rearrangement of elusive tertiary carbocations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
