Cobalt(III)-Catalyzed C–H Amidation of 7-Azaindoles with Dioxazolones: Synthesis of 7-Azaindole Amidated Derivatives

Cobalt(II)-Catalyzed C-H and N-H Functionalization of 1-Arylpyrazolidinones with Dioxazolones as Bifunctional Synthons

Dioxazolone has been attractive as an important synthon for a direct C-H amidation through a nitrene intermediate or Curtius rearrangement to form the isocyanate. However, the combination of two reaction models of dioxazolone has not been reported. Herein, a cobalt-catalyzed C-H and N-H functionalization of 1-arylpyrazolidinones with dioxazolones was developed. The dioxazolones acted as an amidated and carboxamidated reagent. Three C-N bonds were formed in a "one-pot" manner, which promoted the requirement of synthetic diversity.

An Approach to Vinylidenequinazolines from Isoxazoles and Dioxazolones

An effective strategy for the synthesis of vinylidenequinazolines has been efficaciously developed, which involves Rh(III)-assisted C-H amidation followed by ring-opening and intramolecular annulation. This protocol shows a straightforward way to construct diverse quinazoline units with a wide functional group compatibility from readily available isoxazoles and dioxazolones.

N-Aroyloxycarbamates as switchable nitrogen and oxygen precursor: Ir/Cu controlled divergent C–H functionalization of heteroarenes

Chemodivergent control in the functionalization of nitrogen-directed aromatic C–H bonds has been achieved by a switchable catalyst.

Cu(II)-Catalyzed C-N, C-O, C-Cl, C-S, and C-Se Bond Formation via C(sp2)-H Activation Using 7-Azaindole as an Intrinsic Directing Group

A general protocol has been developed for the construction of carbon-heteroatom (C-N, C-Cl, C-O, C-S, and C-Se) bonds using the bench stable, earth-abundant, and environmentally benign copper catalyst. Only oxygen is sufficient to regenerate the copper catalyst. Control experiments suggested that the proto-demetalation step is reversible. Depending on the coupling partner, the reaction follows either disproportionation or radical pathways to complete the catalytic cycle. The synthetic utility of the developed protocol has been demonstrated via various functional group transformations.

Rhodium(III)-Catalyzed Regioselective C(sp2)-H Functionalization of 7-Arylpyrazolo[1,5-a]pyrimidines with Dioxazolones as Amidating Agents

Rh(III)-catalyzed C-H functionalization of 7-arylpyrazolo[1,5-a]pyrimidines was developed wherein the pyrazolo[1,5-a]pyrimidine moiety is reported for the first time to direct the C-H bond activation. Various 7-arylpyrazolo[1,5-a]pyrimidines underwent smooth C-H amidation with alkyl-, aryl-, and heteroaryl-substituted dioxazolones to afford the products in moderate to good yields. Mechanistic studies suggest that a six-membered rhodacycle intermediate involving N1 might play a key role in the regioselective catalytic cycle.

Ru(ii)-Catalyzed C6-selective C–H amidation of 2-pyridones

An efficient Ru-catalyzed C6 site-selective amidation of 2-pyridones has been accomplished with dioxazolone under mild conditions.