Cross-Dehydrogenative C–H Amination of Indoles under Aerobic Photo-oxidative Conditions

A novel cross-dehydrogenative C­(sp²)–H amination catalyzed by an organic photocatalyst is reported. The reaction is mediated by 2-<i>tert</i>-butylanthraquinone as a photocatalyst, harmless visible light, and aerobic oxygen as the sole oxidant without a transition-metal catalyst and or external oxidant

Photo-oxidative Cross-Dehydrogenative Coupling-Type Reaction of Thiophenes with α‑Position of Carbonyls Using a Catalytic Amount of Molecular Iodine

A metal-free photo-oxidative intermolecular C–H/C–H coupling reaction of thiophenes is demonstrated with carbonyls using a catalytic amount of molecular iodine. In this system, molecular oxygen in the air acted as a terminal oxidant to regenerate molecular iodine. A mechanistic study was also performed

Chiral-Anion-Dependent Inversion of Diastereo- and Enantioselectivity in Carbonyl Crotylation via Ruthenium-Catalyzed Butadiene Hydrohydroxyalkylation

The ruthenium catalyst generated in situ from H₂Ru­(CO)­(PPh₃)₃, (<i>S</i>)-SEGPHOS, and a TADDOL-derived phosphoric acid promotes butadiene hydrohydroxyalkylation to form enantiomerically enriched products. Notably, the observed diastereo- and enantioselectivity is the opposite of that observed using BINOL-derived phosphate counterions in combination with (<i>S</i>)-SEGPHOS, the same enantiomer of the chiral ligand. Match/mismatch effects between the chiral ligand and the chiral TADDOL-phosphate counterion are described. For the first time, single-crystal X-ray diffraction data for a ruthenium complex modified by a chiral phosphate counterion are reported

One-pot Sequential Direct C–H Bond Arylation of Azoles Catalyzed by [Pd(phen)₂](PF₆)₂: Synthetic Methods for Triarylated Azoles

Synthetic methods for triarylated azoles containing three different aryl groups via one-pot sequential multiple C–H bond arylations are described. The one-pot sequential diarylation of C5-monoarylated azoles was achieved by the simple sequential addition of two different aryl iodides with a [Pd­(phen)₂]­PF₆ catalytic system. The one-pot triarylation of <i>N</i>-methylimidazole was achieved by the combination of a previously reported Pd­(OAc)₂–P­(2-furyl)₃ system and the present [Pd­(phen)₂]­PF₆ system. In this case, portionwise addition of aryl halide, base and the catalyst in the final step significantly improved the overall yield of the desired triarylated product. These protocols led to triarylated azoles without a loss of efficiency compared to the corresponding previously reported stepwise syntheses via direct C–H bond arylation

Sequential Photo-oxidative [3 + 2] Cycloaddition/Oxidative Aromatization Reactions for the Synthesis of Pyrrolo[2,1‑<i>a</i>]isoquinolines Using Molecular Oxygen as the Terminal Oxidant

We report an efficient method for the synthesis of pyrrolo­[2,1-<i>a</i>]­isoquinoline derivatives using sequential [3 + 2] cycloaddition/oxidative aromatization reactions catalyzed by methylene blue with fluorescent light irradiation under an oxygen atmosphere. The products were obtained in moderate to good yields

Photoinduced Generation of Acyl Radicals from Simple Aldehydes, Access to 3‑Acyl-4-arylcoumarin Derivatives, and Evaluation of Their Antiandrogenic Activities

A novel photocatalysis to construct the 3-acyl-4-arylcoumarin framework from simple aldehyde with ynoate is described. The reaction proceeded through an acyl radical intermediate generated by hydrogen atom abstraction from aldehyde, followed by reaction with ynoate and then cyclization to afford coumarins. This valuable radical cyclization reaction gave over 20 coumarin derivatives in moderate to good yields with inexpensive 2-^<i>t</i>Bu-anthraquinone as a catalyst. In addition, synthetic coumarins were investigated for 5α-dihydrotestosterone (DHT)-induced secretion of prostate-specific antigen (PSA) levels and cell proliferation of androgen-dependent CWR22Rv1 cells