Rhodium catalyzed C–C bond cleavage/coupling of 2-(azetidin-3-ylidene)acetates and analogs

Abstract

The tandem “conjugate addition/β-C cleavage/protonation” process (CCP) is reported.

Palladium/Copper Cocatalyzed C–H Activation and C–C Bond Regioselective Cleavage Reaction for the Synthesis of Fused Chromeno Quinolines

“…In the 1950s, heterolytic fragmentations were considered to be advanced methods for cleaving C­(sp 3 )–C­(sp 3 ) bonds . Until now, C–C bond cleavage reaction has made great achievements by the groups of Song and Jiao, Xu, Kakiuchi, Wei, Ouyang and Xie, Han, Hyodo, Xiao and Zhou, our work, and others . For example, in 2017, Song and Jiao et al reported an allylic C–C bond cleavage reaction of olefins to synthesis of cinnamyl aldehydes in the presence of alkyl azides, DDQ, and TFA .…”

“…3 In the 1950s, heterolytic fragmentations were considered to be advanced methods for cleaving C(sp 3 )− C(sp 3 ) bonds. 4 Until now, C−C bond cleavage reaction has made great achievements by the groups of Song and Jiao, 5 Xu, 6 Kakiuchi, 7 Wei, 8 Ouyang and Xie, 9 Han, 10 Hyodo, 11 Xiao and Zhou, 12 our work, 13 and others. 14 12 The fused chromeno quinolines have shown important roles in biological, medicinal, and fluorescence areas (Figure 1).…”

“…In 2018, Xu et al reported a cascade method for synthesis of enantiopure chroman-2-one and dihydrobenzofuran derivatives by the C–C bond cleavage of cyclopropenones . In 2019, Ouyang and Xie et al reported the Rh-catalyzed β-C cleavage/coupling reaction to synthesize the α,β-unsaturated products by 2-(azetidin-3-ylidene)­acetates and aryl boronic acids . In the same year, Han et al reported an FeCl 3 -catalyzed and ambient air oxidative Csp 3 –Csp 2 bond cleavage of allylarenes for synthesis of aryl aldehydes at room temperature .…”

Solvent-Directed Transition Metal-Free C–C Bond Cleavage by Azido-1,3,5-triazines and Their Stability-Reactivity Paradox

“…Selective carbon–carbon bond (C–C) cleavage reactions have been utilized as powerful tools for the installation of functional groups and new connections. , Typically, C–C cleavage is achieved by β-scission of radicals − or cleavage of strained rings. − Since most of these cleavage reactions need transition metals as catalysts , and harsh reaction conditions, selective cleavage of unstrained C–C bonds at ambient conditions without using transition metal catalysts remains as a challenge.…”

“…1,2 Typically, C−C cleavage is achieved by β-scission of radicals 3−6 or cleavage of strained rings. 7−10 Since most of these cleavage reactions need transition metals as catalysts 11,12 and harsh reaction conditions, selective cleavage of unstrained C−C bonds at ambient conditions without using transition metal catalysts remains as a challenge.…”