Multisubstituted N-fused heterocycles via transition metal-catalyzed cycloisomerization protocols.
Two complementary protocols for assembly of multisubstituted N-fused heterocycles have been developed. It was demonstrated that 1,3-disubstituted N-fused heterocycles, including indolizines, pyrroloquinoxalines, and pyrrolothiazoles can easily be synthesized via an exceptionally mild and efficient method involving a novel silver-catalyzed cycloizomerization of propargyl-containing heterocycles. Alternatively, 1,2-disubstituted heterocycles can be accessed through the novel cascade transformation involving an alkyne-vinylidene isomerization with concomitant 1,2-shift of hydrogen, silyl, stannyl, or germyl groups. This mild and simple method allows for selective and highly efficient synthesis of indolizines, pyrroloisoquinolines, pyrroloquinoxalines, pyrrolopyrazines, and pyrrolothiazoles.
Seregin
Ilya V
IV
Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., Chicago, Illinois 60607-7061.
Schammel
Alex W
AW
Gevorgyan
Vladimir
V