Cu^II-Catalyzed Coupling with Two Ynone Units by Selective Triple and Sigma C–C and C–H Bond Cleavages

Abstract

We report a new copper-catalyzed [2 + 2 + 1] annulation process through the selective cleavage of sigma and triple C–C and C–H bonds using two ynone units. This new methodology involves breaking multiple chemical bonds in a single operation, including CC, C–C, C–H, and N–O. These high-value adducts lead to a diverse collection of synthetically challenging trisubstituted indolizines by the simultaneous engagement of different bond-breaking events and show excellent fluorescence in green aqueous solutions.

Copper-Catalyzed Formal [4 + 1] Annulation toward Diverse Trifunctionalized Indolizines from Pyridinium 1,4-Zwitterionic Thiolates and Diazos

“…Indolizines are important nitrogen-containing motifs, which have recently received a great deal of attention due to their promising applications in pharmaceutical molecules, electroluminescent materials, and fluorescent dyes. , Subsequently, tremendous endeavors for the production of indolizine derivatives have been devoted. , Recently, we successfully achieved regioselective C–H diselenylation, dicarbonylation, carboxamidation, dithiocarbamation, disulfuration, and deconstructive cycloaromatization of indolizines, to access a library of functionalized indolizines (Scheme a). Despite these advances, the construction of indolizine cores bearing some important functional groups such as −CO 2 R, −CO 2 NR 2 , −CF 3 , −CN, and −(O)P(OR) 2 has not been disclosed yet in the literature.…”

Solvent-Dependent Selective Synthesis of CF3-Tethered Indazole Derivatives Based on Multiple Bond Activations

“…By taking advantage of the diversified reactivity of CF 3 -ynones, Wang et al recently disclosed a Rh-catalyzed redox-neutral [3 + 3] annulation of anilines with CF 3 -ynones to give 2-trifluoromethyl quinolines through C–H alkenylation followed by intramolecular condensation (Scheme e) . Inspired by these elegant pioneering achievements and in continuation of our own study in C–H bond activation, − we were interested in investigating the reaction of 1-arylpyrazolidinones with CF 3 -ynones with the aim to develop synthetic protocols to furnish CF 3 -substituted heterocycles. It was initially envisioned by us that 1-phenylpyrazolidinone might undergo a C­(sp 2 )–H alkenylation with CF 3 -ynone to give intermediate A , which might then take part in an intramolecular N-nucleophilic addition to give CF 3 -substituted benzodiazepine derivative B (Scheme f).…”

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

“…11 Therefore, numerous synthetic methods have been developed to construct indolizine derivatives in the past decade. 12,13 We have long been committed to the construction of indolizine derivatives. 14 As part of our continuous research, herein we report an efficient metal-free annulative vinylene transfer protocol for the synthesis of benzo-fused indolizines via [3 + 2] cycloadditions of N -ylides with vinylene carbonate (Scheme 1c).…”