Gold-catalysed generation of diol equivalents from epoxides and their intramolecular reaction with C≡C bonds to generate bicyclicketals is presented. This reaction essentially involves the formation of an acetonide, which subsequently cyclises on the alkyne intramolecularly under gold catalysis conditions. This method could be extended to make optically pure bicyclicketals. Deuterium incorporation
Catalytic, Enantioselective <i>Syn</i>-Oxyamination of Alkenes
作者:Emily M. Mumford、Brett N. Hemric、Scott E. Denmark
DOI:10.1021/jacs.1c06750
日期:2021.8.25
2-oxyamination of alkenes using selenium(II/IV) catalysis with a chiral diselenide catalyst is reported. This method uses N-tosylamides to generate oxazoline products that are useful both as protected 1,2-amino alcohol motifs and as chiral ligands. The reaction proceeds in good yields with excellent enantio- and diastereoselectivity for a variety of alkenes and pendant functional groups such as sulfonamides
The opening reaction of epoxides by monochloroborane-dimethylsulfide 1 proceeds by oxygen anchimeric assistance in a regio and diastereoselective manner to give the corresponding anti chlorohydrins.
diphenylvinyl sulfonium triflate with nucleophiles and either aldehydes or imines gives epoxides and aziridines, respectively, in a three-component reaction. cis-Aziridines could be formed in good diastereomeric ratio, and the selectivity was correlated to the reactivity of the imine. This represents the first study of cis/trans selectivity in the reactions of imines with non-stabilized sulfur ylides.