Regioselective syntheses of the indolopyridine alkaloids nauclefine, angustine, dihydroangustine and naucletine from a common intermediate
Abstract
A short, flexible route for the synthesis of the title indolopyridine alkaloids consisting of the cyclization of enamide 3, followed by introduction of the requisite pyridine substituent by Pd0-catalysed reactions from the resulting pentacyclic bromo intermediate 4 is reported.