Transition metal-free annulative vinylene transfer via the 1,3-dipolar reaction of N-ylides: access to benzo-fused indolizines

Abstract

An efficient metal-free annulative vinylene transfer protocol for the synthesis of benzo-fused indolizines via the 1,3-dipolar cycloadditions of N-ylides with vinylene carbonate has been developed. The vinylene carbonate serves as...

Tandem Isomerization/α,β-Site-Selective and Enantioselective Addition Reactions of N-(3-Butynoyl)-3,5-dimethylpyrazole Induced by Chiral π–Cu(II) Catalysts

“…The utility of bench-stable isoquinolinium ylides in the enantioselective 1,3-dipolar cycloadditions has attracted substantial attention from the scientific community in very recent years . This stems from their proven convenient and efficient role for constructing pyrroloisoquinoline scaffolds, which are crucial moieties in numerous natural products and pharmaceutically active compounds .…”

DBU‐Promoted [3+2] Cyclization/Retro‐Mannich Cascade Reaction of N‐Aminoisoquinolinium and N‐Aminoquinolinium Derivatives with para‐Quinone Methides

“…[9,10] In 2018, Shi and coworkers reported the first [4 + 2] cyclization/retro-Mannich reaction cascade of p-QMs with Pd-containing 1,4-dipoles generated in situ from vinyl benzoxazinanones (Scheme 1d). [11] Inspired by this work and our previously successful application of iminopyridinium derivatives as 1,3-dipoles, [7,12] we proposed that the [3 + 2] cyclization reaction between N-ylide I (formed from N-aminoisoquinolinium derivatives 1 with a base) [6e,7a] and p-QMs would be realized via a domino 1,6-addition/dearomatization to offer the cyclization product II (Scheme 2). However, the experimental results indicate that no [3 + 2] cyclization product II was detected.…”

One-step synthesis of cyanated pyrazolo[1,5-a]pyridines utilizing N-aminopyridines as a 1,3-dipole and a nitrogen source

“…10 b We have very recently developed a [3 + 2] cyclization of N -iminopyridinium ylides with vinyl carbonate to synthesize pyrazolo[1,5- a ]pyridine and pyrazolo[1,5- a ]pyridin-2-ol derivatives. 11 To further explore the novel reactivity mode of N -aminopyridinium ylides and in continuation of our research on the construction of functionalized N-heterocycles, 12 herein, we report the successful one-step synthesis of cyanated pyrazolo[1,5- a ]pyridines utilizing N -aminopyridines as a 1,3-zwitterion and a nitrogen source via a metal-free [3 + 2] annulation reaction (Scheme 1c). Also, 3-cyano pyrazolo[1,5- a ]pyrazine derivatives could be obtained by this approach.…”