Sustainable Radical Reduction through Catalytic Hydrogen Atom Transfer

Radikale und Übergangsmetallkatalyse – eine Allianz par excellence zur Steigerung von Reaktivität und Selektivität in der organischen Chemie

“…[16] Kürzlich entwickelten Gansäuer und Mitarbeiter eine katalytische Methode für die reduktive Ringöffnung von Epoxiden (Schema 7). [17] [18] deutet an, dass solche Wasserstoffübertragungen mit Geschwindigkeitskonstanten bis zu 10 9 m À1 s À1 ablaufen können. [19]…”

Radicals in organic synthesis. Part 1

“…80 An intriguing new catalytic system has been developed that employs hydrogen gas (H 2 ) as the hydrogen-atom source in the reduction of the terminal radical. 81 This reaction effectively combines the catalytic Cp 2 TiCl 2 /Mn/lutidine$HCl conditions with catalytic hydrogenation mediated by Wilkinson's catalyst. The radical generated by epoxide ring opening first abstracts a hydrogen from the rhodium dihydride species to give the alkoxytitanocene(IV) species and a monohydride complex.…”

Catalysis Involving the H• Transfer Reactions of First‐Row Transition Metals

“…However, the strength of an M -H bond is particularly important in determining the rate of its H • transfer reactions. Moving from Cp(CO) 3 MoH to the (structurally similar) Cp(CO) 3 Gans ä uer and coworkers have developed a tandem catalytic approach to reductive epoxide opening that employs H • transfer from a dihydride complex (Scheme 1.2 ) [32,33] . The carbon -centered radical that arises from ratedetermining epoxide opening with Cp 2 TiCl abstracts H • from the H 2 adduct of Wilkinson ' s catalyst.…”