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.
Cu(I)-Catalyzed Cross-Coupling Rearrangements of Terminal Alkynes with Tropylium Tetrafluoroborate: Facile Access to Barbaralyl-Substituted Allenyl Acid Esters and 7-Alkynyl Cycloheptatrienes
cycloisomerization process from the π-alkyne–Cu(I) complex to afford the copper carbene intermediate, followed by migratory insertion with the second terminal alkyne to afford the barbaralyl-substituted allenyl acid esters. In addition, we develop a mild and highly efficient Cu(I)-catalyzed cross-coupling protocol to synthesize 7-alkynyl cycloheptatrienes that has a broad functional group tolerance and is applicable