Gold for the Generation and Control of Fluxional Barbaralyl Cations
作者:Paul R. McGonigal、Claudia de León、Yahui Wang、Anna Homs、César R. Solorio-Alvarado、Antonio M. Echavarren
DOI:10.1002/anie.201207682
日期:2012.12.21
comparison with the shape‐shifting barbaralylcation, which exists as a mixture of 181 400 degenerate forms. Gold‐catalyzed cycloisomerizations of 7‐alkynyl cyclohepta‐1,3,5‐trienes were found to proceed via fluxionalbarbaralyl intermediates (see scheme). The evolution of the intermediates into 1‐ or 2‐substituted indenes could be controlled by the choice of gold complex.
Gold(I) Carbenes by Retro-Buchner Reaction: Generation and Fate
作者:Yahui Wang、Paul R. McGonigal、Bart Herlé、Maria Besora、Antonio M. Echavarren
DOI:10.1021/ja411626v
日期:2014.1.15
The fate of the aryl gold(I) carbenes generated by retro-Buchner reaction of ortho-substituted 7-aryl-1,3,5-cycloheptatrienes is dependent on the constitution of the ortho substituent. Indenes and fluorenes are obtained by intramolecular reaction of highly electrophilic gold(I) carbenes with alkenes and arenes. According to density functional theory calculations, the gold-catalyzed retro-Buchner process
1-aryl-2-(o-hydroxymethylphenyl)ethanols from readily available 3-substituted phthalides are described. Their reaction with polyphosphoric acid is a route, superior in convenience and yield, to 2-arylindenes.
A process is disclosed for preparing 2-aryl-substituted indenes by reacting an indene with an arene compound substituted with an halogen atom, preferably a iodine atom, or with an organosulphonate group, said reaction being carried out in a basic medium in the presence of a palladium catalyst. The compounds obtainable by this process can be used to prepare metallocene compounds with transition metals such as titanium, zirconium or hafnium, which are useful as catalyst components in the polymerization of olefins.