Synthesis of carbinoxamine via α-C(sp³)–H 2-pyridylation of O, S or N-containing compounds enabled by non-D–A-type super organoreductants and sulfoxide- or sulfide HAT reagents

Abstract

The radical cations of tertary amines (R3N) have been well-established as the precursors of HAT reagents in the photochemical transformations. Similarly, thiols and thioacids bearing SH-groups have also been widely...

Synthesis of α-Hydroxyl and α-Amino Pyridinyl Esters via Photoreductive Dual Radical Cross-Coupling

“…And what should be noted is that it is necessary to use more than 2 equiv of amines to complete the reaction. This phenomenon indicates that there might be 1 equiv of electron donor (amine) for the reduction of 1 and the other equivalent for the reduction of 2. , Therefore, the dual radical cross-coupling might be a reasonable mechanism (Figure d).…”

“…This phenomenon indicates that there might be 1 equiv of electron donor (amine) for the reduction of 1 and the other equivalent for the reduction of 2. , Therefore, the dual radical cross-coupling might be a reasonable mechanism (Figure d).…”

“…On the other hand, the emergence of photocatalytic reactions enables the introduction of functional groups into organic molecules by changing the reaction pathway. − In our continuing efforts to develop novel and practical redox reactions, − we have developed a non-donor–acceptor type super-organoreductant CBZ6 , which bears a highly twisted single carbazole core. It demonstrates a strong * E ox potential (* E ox = −2.16 V vs SCE) and enabled the umpolung of α,β-unsaturated amides to undergo α-nucleophilic addition instead of the normal β-addition .…”

Reductive Cleavage of C–X or N–S Bonds Catalyzed by Super Organoreductant CBZ6

“…The dehalogenation has been extended to the phosphorylation of aryl chlorides (Scheme ). Inspired by our previous work using sulfoxide as HAT reagent in 2-pyridylation of esters, 10 mol % of diphenyl sulfoxide proved to be an efficient HAT reagent in the phosphorylation using HCO 2 Na as reductant. Diethyl arylphosphonates were obtained in 83–98% yields ( 6a – f ).…”

Transalkylation via C–N Bond Cleavage of Amines Catalyzed by Super Organophotoreductant CBZ6

“…On the basis of the experimental evidence, a plausible mechanism is proposed in Scheme 4. Radical B is generated via a SET-deprotonation process, 7,8 followed by the addition to 2phenyl isocyanobenzene 1 to afford radical C. Radical B is supported by Scheme 4, eq 3. The cascade intramolecular radical addition gives D. Radical D transforms to the much more stable N-α-C radical E. The electron injection by excited super organoreductant CBZ6 yields anion F. This step is supported by Scheme 4, eq 4.…”