A Sequential Activation of Alkyne and C–H Bonds for the Tandem Cyclization and Annulation of Alkynols and Maleimides through Cooperative Sc(III) and Cp*-Free Co(II) Catalysis

Abstract

Metrics & MoreArticle Recommendations * sı Supporting InformationABSTRACT: [4 + 2] oxidative Diels−Alder reaction of readily available alkynols with maleimide is achieved for the rapid access of pthalimidefused multicyclic compounds. The reaction is proposed to go through a sequence of Sc(OTf) 3 -catalyzed electrophilic cyclization, ligand exchange with Cp*-free cobalt, and C−H activation followed by maleimide insertion.

Recent advances in transition-metal-catalyzed directed C–H alkenylation with maleimides

“…In 2020, Reddy developed rapid access to phthalimide-fused multicyclic compounds via the oxidative [4 + 2] Diels–Alder reaction of readily available alkynols with maleimides (Scheme 14). 35 This cooperative Co( ii )-Sc( iii ) catalytic annulation is proposed to proceed through a sequential electrophilic oxy cyclization, C–H activation and maleimide insertion. The authors proposed a mechanism as shown in Scheme 14.…”

Harnessing Rhodium-Catalyzed C–H Activation: Regioselective Cascade Annulation for Fused Polyheterocycles

“…formation of multicyclic systems in one pot, remains elusive. As part of an overarching aim to develop novel reactivities of activated alkynes, we herein describe a cascade annulation of 4-hydroxy-2-alkynoates with homopropargylic precursors to achieve fused polyheterocycles (Scheme e).…”

Copper(I)-Mediated Cascade Annulation via Dual C–H/C–H Activation: Access to Benzo[a]carbazolic AEEgens

“…In this regard, several pioneering works have been reported utilizing expensive 4d and 5d metals . However, from the fundamental and application perspective, their high cost, low earth abundance, and toxic nature demand the use of earth-abundant and innocuous 3d metals . In this context, despite the significant advances made in C–H activation using 3d metals, Cu salts are far less scrutinized for the cascade annulation .…”