New methods for the synthesis of naphthyl amines; application to the synthesis of dihydrosanguinarine, sanguinarine, oxysanguinarine and (±)-maclekarpines B and C
作者:Matthew R. Tatton、Iain Simpson、Timothy J. Donohoe
DOI:10.1039/c4cc05209a
日期:——
A new method for preparing naphthyl amines from 1,5 unsaturated dicarbonyl precursors is described; the utility of this new method was proven in the syntheses of several natural products, all containing the benzo[c]phenanthridine core and enabled by a radical promoted cyclisation of the naphthyl amine products formed in the key cyclisation.
Enantioselective Synthesis of 2,6-<i>cis</i>-Disubstituted Tetrahydropyrans via a Tandem Catalytic Asymmetric Hydrogenation/Oxa-Michael Cyclization: An Efficient Approach to (−)-Centrolobine
A highly efficient one-pot process via a tandemreaction of catalytic asymmetric hydrogenation and oxa-Michael cyclization for the synthesis of 2,6-cis-disubstituted tetrahydropyrans has been developed (ee up to 99.9%, cis/trans-selectivity up to 99:1). This method provides a concise route to (−)-centrolobine (68.8% yield, three steps).