Intramolecular Oxidative C−H Coupling for Medium-Ring Synthesis

Abstract

An oxidative C-H coupling is described for medium-ring synthesis.

Synthesis of Cyclopentadiindolyl Spirooxindoles via Palladium‐catalyzed Intramolecular Oxidative Indole‐Indole Coupling Reaction

“…As shown in Table , the reaction of 1a in the presence of Pd(OAc) 2 , Cu(OAc) 2 , and K 2 CO 3 in N,N ‐dimethylacetamide (DMA) at 100 °C afforded 2a in low yield (37%) for 18 h (entry 1). 8a When we elevated the reaction temperature to 140 °C, the yield of 2a decreased (entry 2).…”

“…The reaction of 1a in the presence of K 3 Fe(CN) 6 in alkaline solution also did not produce 2a . Thus, we examined the synthesis of 2a by palladium‐catalyzed oxidative arene‐arene coupling reaction conditions …”

Intramolecular Oxidative Arylations in 7‐Azaindoles and Pyrroles: Revamping the Synthesis of Fused N‐Heterocycle Tethered Fluorenes

“…Taken together,o nly af ew of these fused isoindolines have been reported; these have been prepared by using prefunctionalized substrates through direct arylation or cross-coupling reactions. Distinct from the current approaches, [8] our protocold oes not require any C-3 substituent on the nitrogen heterocycles. We then investigatedt he synthesis of N-heterocycle fused chiral isoindolines,w hich have little precedence.…”

“…7‐Azaindole or pyrrole fused isoindolines have traditionally been synthesized by using transition‐metal‐catalyzed intramolecular direct or cross‐coupling reactions . Although a few reports of intramolecular oxidative couplings are available, including a pioneering study by Greaney et al . (largely in 3‐substituted indoles yielding medium‐ring fused indoles), and subsequently by Bao, Guo, and DeBoef (in benzimidazoles and purines affording benzimidazole fused isoindolines), they are limited to the nitrogen heterocycles that have a substituent or nitrogen– at the 3‐position.…”

Pd‐Catalyzed Synthesis of Oxygen‐Containing Heterocycles

“…Medium-ring-containing biaryls are generally difficult to access by classical routes; thus development of new approach to this structure is highly attractive. In 2011, Greaney reported the intramolecular dehydrogenative coupling of indoles and other arenes to synthesize medium-ring heterocycles [19]. In the investigation of this double C-H activation reaction, three oxazapane derivatives were obtained in good yields by the catalysis of Pd(OAc) 2 (Scheme 3.5).…”