Biphilic Organophosphorus-Catalyzed Intramolecular C_sp²-H Amination: Evidence for a Nitrenoid in Catalytic Cadogan Cyclizations.

ABSTRACT: A small-ring phosphacycloalkane (1,2,2,3,4,4-hexamethylphosphetane, 3) catalyzes intramolecular C-N bond forming heterocyclization of o-nitrobiaryl and -styrenyl derivatives in the presence of a hydrosilane terminal reductant. The method provides scalable access to diverse carbazole and indole compounds under operationally trivial homogeneous organocatalytic conditions, as demonstrated by 17 examples conducted on 1 g scale. In situ NMR reaction monitoring studies support a mechanism involving catalytic P^III/P^V═O cycling, where tricoordinate phosphorus compound 3 represents the catalytic resting state. For the catalytic conversion of o-nitrobiphenyl to carbazole, the kinetic reaction order was determined for phosphetane catalyst 3 (first order), substrate (first order)

SUBMITTER: Nykaza TV 

PROVIDER: S-EPMC5831529 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature