Diazo compounds and palladium-aryl complexes: trapping the elusive carbene migratory insertion organometallic products

The reactions of Pd-aryl complexes with diazo compounds N₂CH-CHCHPh and N₂CHPh allowed us to isolate the organometallic products formed right after the migratory insertion of a non-stabilized CHR carbene into the Pd-aryl bond. η³-Allylic and η³-benzylic palladium complexes were formed respectively. This is compelling experimental evidence for the key step in the palladium-catalyzed cascade transformations of diazo derivatives leading to multiple C-C or C-X bond formation.

Palladium-catalyzed carbene coupling polymerization: synthesis of E-poly(arylene vinylene)s

The Pd-catalyzed carbene coupling reaction of N-tosylhydrazones and benzyl bromides has been developed into a polymerization process for the first time, providing an efficient method for the synthesis of poly(arylene vinylene)s (PAVs). This method affords PAVs bearing E-vinylene units predominantly. It can also introduce a CF₃ group on each vinylene carbon atom in the polymer main chain. The polymerization has a broad scope and the resultant polymers exhibit interesting optical properties and good thermal stabilities.

Cu(II)-Catalyzed Synthesis of 4-(1,4,5,6-Tetrahydropyridin-3-yl)-1,4-dihydroisoquinolin-3-ones from 4-Diazoisoquinolin-3-ones

We report a simple, efficient, and highly selective C-H bond insertion of copper carbenes generated in situ from 4-diazo-1,4-dihydroisoquinolin-3-ones into β-C(sp²)-H bonds of N-sulfonyl enamides, which gave a series of 4-(1,4,5,6-tetrahydropyridin-3-yl)-1,4-dihydroisoquinolin-3(2H)-ones in good to excellent yields. Operationally simple and mild reaction conditions, a cheap catalyst, readily accessible starting materials, and a broad substrate scope are the merits of this reaction.

Synthesis of Polyallenoates through Copper-Mediated Cross-Coupling of Dialkynes and Bis-α-Diazoesters

The copper-catalyzed cross-coupling of alkynes and α-diazoesters have been applied in the synthesis of polyallenoates for the first time. The polymerization tolerated various functional groups and afforded the polyallenoates with...

Polymerization with Cu(I)-Catalyzed Doyle-Kirmse Reaction of Bis(allyl sulfides) and Bis(α-diazoesters)

Cu(I)-catalyzed Doyle-Kirmse reaction has been successfully introduced into polymer chemistry for the first time. A series of new type of sulfur-containing polymers were efficiently synthesized from various allyl sulfides and...

A mechanistic investigation of the Pd-catalyzed cross-coupling between N-tosylhydrazones and aryl halides

The cross-coupling of N-tosylhydrazones and aryl halides forms carbon-carbon bonds, producing 1,1-disubstituted alkenes. Though it has proven extremely useful in several fields of chemistry, its mechanism remains experimentally unexplored. Combining benchtop NMR and real-time mass spectrometry afforded the ability to monitor the catalytic intermediates as well as the rate of product formation.

Synthesis of 8-Alkoxy-5H-isochromeno[3,4-c]isoquinolines and 1-Alkoxy-4-arylisoquinolin-3-ols through Rh(III)-Catalyzed C-H Functionalization of Benzimidates with 4-Diazoisochroman-3-imines and 4-Diazoisoquinolin-3-ones

Rh(III)-catalyzed C-H activation/annulation of benzimidates with 4-diazoisochroman-3-imines furnished 8-alkoxy-5H-isochromeno[3,4-c]isoquinolines in moderate to excellent yields with a broad range of substrate scope. The reaction was carried out under mild reaction conditions and could be scaled up with practical usage. Similar reaction between benzimidates and 4-diazoisoquinolin-3-ones provided 1-alkoxy-4-arylisoquinolin-3-ols in excellent yields. Moreover, the synthesized products could be conveniently transformed to the corresponding heterocycles with a 1,8-naphthyridinone or isochromenopyridinone core, which are privileged structures in medicinal chemistry.