Rhodium(iii)-catalyzed alkylation of primary C(sp(3))-H bonds with α-diazocarbonyl compounds

A Rh(iii)-catalyzed cascade C–H functionalization/cyclization reaction of salicylaldehydes with diazomalonates for the synthesis of 4-hydroxycoumarin derivatives

A cascade C–H functionalization/cyclization reaction of salicylaldehydes with α-diazomalonates has been developed for the synthesis of 4-hydroxycoumarin derivatives under rhodium(iii) catalysis.

Rh(iii)-catalyzed regioselective intermolecular N-methylene Csp3-H bond carbenoid insertion

A Rh(iii)-catalyzed regioselective intermolecular carbenoid insertion into the N-methylene Csp³-H bond of acyclic aliphatic amides has been achieved, taking advantage of bidentate-chelation assistance. This methodology has been successfully applied to a broad range of linear and branched-chain N-alkylamides, thus providing a practical method for the assembly of diverse beta-amino esters. Mechanism studies and density functional theory (DFT) calculations revealed that a singlet Fischer type carbene insertion via an outer-sphere pathway was involved in this N-methylene Csp³-H bond carbenoid insertion.

Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion

Transition-metal-catalyzed cross-coupling reactions have been well-established as indispensable tools in modern organic synthesis. One of the major research goals in cross-coupling area is expanding the scope of the coupling partners. In the past decade, diazo compounds (or their precursors N-tosylhydrazones) have emerged as nucleophilic cross-coupling partners in C-C single bond or C═C double bond formations in transition-metal-catalyzed reactions. This type of coupling reaction involves the following general steps. First, the organometallic species is generated by various processes, including oxidative addition, transmetalation, cyclization, C-C bond cleavage, and C-H bond activation. Subsequently, the organometallic species reacts with the diazo substrate to generate metal carbene intermediate, which undergoes rapid migratory insertion to form a C-C bond. The new organometallic species generated from migratory insertion may undergo various transformations. This type of carbene-based coupling has proven to be general: various transition metals including Pd, Cu, Rh, Ni, Co, and Ir are effective catalysts; the scope of the reaction has also been extended to substrates other than diazo compounds; and various cascade processes have also been devised based on the carbene migratory insertion. This review will summarize the achievements made in this field since 2001.

Facile synthesis of 1-aminoindoles via Rh(iii)-catalysed intramolecular three-component annulation

A simple and efficient procedure to 1-aminoindoles starting from easily available aryl hydrazines, diazo compounds and ketones via a rhodium-catalyzed [3 + 2] annulative coupling reaction.

Rhodium(iii)-catalyzed directed C–H benzylation and allylation of indoles with organosilicon reagents

Rhodium(iii)-catalyzed C2-benzylation and allylation of indoles with organosilicon reagents via chelation-assisted C–H activation has been developed.

Cp*Rh(iii)-catalyzed C(sp3)–H alkylation of 8-methylquinolines in aqueous media

A mild and efficient approach for the cross-coupling reaction of 8-methylquinolines with a range of allylic alcohols in water as a solvent under rhodium(iii) catalysis is described.

Rhodium(iii)-catalyzed regio- and stereoselective benzylic α-fluoroalkenylation with gem-difluorostyrenes

Rh(iii)-Catalyzed fluoroalkenylation of a benzylic C–H bond has been realized under mild conditions with high regio- and stereoselectivity.

Regioselective transition metal- and halogen-free direct dithiolation at C(sp3)–H of nitrotoluenes with diaryl disulfides

Here we describe a potassium tert-butoxide-mediated regioselective direct C–S bond formation at the C(sp³)–H position of nitrotoluenes with disulfides in DMSO at room temperature. The developed reaction generated various dithioacetals in good yields. Further, synthesized dithioacetals were transformed into 4-nitrobenzaldehyde and 7-(bis(phenylthio)methyl)-1H-indole.