Gold-Catalyzed Carbene Transfer to Alkynes: Access to 2,4-Disubstituted Furans
作者:Søren Kramer、Troels Skrydstrup
DOI:10.1002/anie.201200307
日期:2012.5.7
example of a gold‐catalyzed intermolecular addition of carbon ylides to terminal alkynes is reported (see scheme; DCE=dichloroethane, Tf=trifluoromethanesulfonyl). Subsequent intramolecular trapping of the generated gold carbene completes a formal [3+2] cycloaddition, which represents a novel synthesis of 2,4‐disubstituted furans.
Herein, a one-pot, two-step procedure for the diastereoselective synthesis of cyclopropanes bearing trifluoromethyl-substituted all-carbon quaternarycenters has been described. Trifluoromethyl-activated 1,3-enynes undergo cyclopropanation reactions with sulfur ylides under mild reaction conditions without fluoride elimination, which affords the cis-isomer mainly. Interestingly, a sequential TBAF-mediated