Scope and applications of second generation palladium-catalyzed cycloalkenylation. Stereoselective total syntheses of isoiridomyrmecin, isodihydronepetalactone, and α-skytanthine

Abstract

Functionalized bicyclo[3.2.1]octanes, -oxabicyclo-[4.3.0]nonanes, 3-azabicyclo[3.3.0]octanes, and 3-azabicyclo[4.3.0]nonanes were easily synthesized via a second generation palladium-catalyzed cycloalkenylation. Isoiridomyrmecin and isodihydronepetalactone, both of which feature a 3-oxabicyclo[4.3.0]nonane subunit, were stereoselectively synthesized via a second generation palladium-catalyzed cycloalkenylation as the key step. α-Skytanthine, a typical 3-azabicyclo[4.3.0]nonane alkaloid, was also constructed using the same catalytic cyclization protocol.