We report novel iridium(III)-catalyzed reactions that afford substituted indoles via the indirect functionalization of alcohols via C-3 selective alkylation of indoles with alcohols and a one-pot cascade strategy from amino- or nitro-phenyl ethyl alcohols, which incorporates oxidative cyclization and C-3 alkylation.

A greatly improved process has been developed for synthesis of the glutarate derivative 2, a key intermediate required for Pfizer's drug candoxatril. The cationic (R,R)-Me-DuPHOS-Rh catalyst was found to allow highly efficient and enantioselective hydrogenation of a unique carboxylate substrate (5) to afford the desired product in >99% ee and high yield (95%). The robust nature of the process was validated on a 12 kg reaction scale. A novel mechanism for the hydrogenation process is proposed. Through use of a labile eta(6)-benzene-Rh-Me-DuPHOS complex, the postulated catalytic intermediates have been synthesized by independent means. Detailed spectroscopic analyses of these intermediates corroborate the mechanistic hypotheses. Interconversion of these key catalytic intermediates has been demonstrated.