Dramatic rate acceleration in titanocene catalyzed epoxide openings: cofactors and Lewis acid cocatalysis
作者:Andreas Gansäuer、Harald Bluhm
DOI:10.1039/a805246h
日期:——
High synthetic efficiency concerning yield and catalytic turn-over in intermolecular C–C bond forming reactions of radicals derived from epoxides can be achieved by means of hydrogen bonding with cofactors or by Lewis acid cocatalysis.
The preparatively important catalytic opening of epoxides to β-titanoxy radicals via single-electron transfer (SET) is described. These radicals can be reduced to alcohols or participate in C−C bond-forming reactions. A key step in the catalytic cycle is the conceptually novel protonation of titanium−oxygen and −carbon bonds. Our method combines the advantages of radical reactions, e.g., high functional