Direct Access to Furoindolines by Palladium-Catalyzed Intermolecular Carboamination

A versatile Pd-catalyzed intermolecular syn-carboamination
of dihydrofurans giving access to the ubiquitous furoindoline motif
is described. The efficiency of the process relies on the use of Buchwald-type
biarylphosphines and the perfect control for site-selectivity of Pd
insertion across the CC bond. A catalytic sequence consisting
of Heck and carboamination cross-coupling reactions from readily available
dihydrofurans affordsin usually high chemical yields and high
levels of diastereocontrolpoly­(hetero)­cyclic compounds that
would be difficult to access by established methods. Encouraging preliminary
results for the enantioselective carboamination of 2,3-dihydrofurans
are also disclosed.