Cross‐Coupling of α‐Carbonyl Sulfoxonium Ylides with C−H Bonds

Abstract

The functionalization of carbon–hydrogen bonds in non‐nucleophilic substrates using α‐carbonyl sulfoxonium ylides has not been so far investigated, despite the potential safety advantages that such reagents would provide over either diazo compounds or their in situ precursors. Described herein are the cross‐coupling reactions of sulfoxonium ylides with C(sp2)−H bonds of arenes and heteroarenes in the presence of a rhodium catalyst. The reaction proceeds by a succession of C−H activation, migratory insertion of the ylide into the carbon–metal bond, and protodemetalation, the last step being turnover‐limiting. The method is applied to the synthesis of benz[c]acridines when allied to an iridium‐catalyzed dehydrative cyclization.

Silver/Rhodium Relay Catalysis Enables C−H Functionalization of In Situ Generated Isoquinolines with Sulfoxonium Ylides: Construction of Hexahydrodibenzo[a,g]quinolizine Scaffolds

“…On the basis of the results of above control experiments and previous work, [10,13] a mechanism for Ag/Rh relay catalysis reaction is suggested as shown in Scheme 4. Coordination of Ag(I) with the alkyne moiety of 1 a generates an intermediate A, which initiates an intramolecular electrophilic cyclization, producing a cyclized intermediate B.…”

“…As versatile carbene precursors, sulfoxonium ylides [9] were widely ulitized because of their high flexibility, stability and diverse reactivity. In 2017, Aissa [10] and others [11] reported the Cp*Rh(III)-catalyzed CÀ H functionalization of arenes with sulfoxonium ylides as carbene precursors and coupling partners (Scheme 1, b). Although directing group-assisted CÀ H bond function- alization strategies can achieve the desired transformation with high reactivity and selectivity, the limitations of directing group strategy are that directing groups are often difficult to install and manipulate after processes are completed.…”

Comprehensive Overview of Progress in Functionalization of 2‐Pyridone and 2, 4 ‐Dihydroxy Pyridine: Key Constituents of Vital Natural Products

“…Alkylation of 2-pyridone using diene and activated alkenes. Barday et al [110] In terms of scope of pyridone substrate, both EWG/EDG were well tolerated. C-5 substitution, although sterically demanding, gave considerable yield (75 %).…”

“…Inspired by the works of Barday and Janot [110] on use of sulphoxonium ylides for generation of carbene intermediate for functionalization of C−H bonds on arene substrates, Fu et al [111] . devised C ‐6 selective acylmethylation of 2‐pyridones.…”

“…Inspired by the works of Barday and Janot [110] on use of sulphoxonium ylides for generation of carbene intermediate for functionalization of CÀ H bonds on arene substrates, Fu et al [111] devised C-6 selective acylmethylation of 2-pyridones. The treatment consisted the reaction between 2-pyridone (95) and α-benzoyl sulphoxonium ylide (126) in presence of ruthenium catalyst with AgSbF 6 additive in hexafluoro isopropane (HFIP) solvent (Scheme 34).…”