Pd‐Catalyzed [3+2]‐Dehydrogenative Annulation Reactions

Abstract

AbstractThe significance of cross dehydrogenative couplings has increased considerably in recent years. This article revisits the [3+2] C−C/N−C, C−C/O−C and C−C/C−C annulation strategy, recently reported by our group, according to a Pd(II) catalyzed dehydrogenative variant. Our original report relied on Pd(0) catalysis, using α,β‐unsaturated‐γ‐oxy carbonyls as bis‐electrophiles and resonance‐stabilized acetamides or 3‐oxoglutarates as C/N and O/C or C/C bis‐nucleophiles, respectively. In this more modern and straightforward Pd(II)‐catalyzed dehydrogenative approach, β,γ‐unsaturated carbonyl derivatives replace α,β‐unsaturated‐γ‐oxy carbonyls as bis‐electrophiles. Our study includes experimental optimization and showcases the synthetic versatility in the formation of diverse heterocyclic structures, such as bicyclic lactams, furo‐cycloalkanones and bicycloalkane‐diones. Furthermore, a mechanism is proposed to elucidate the underlying processes involved in these reactions.