Visible-light driven acetoxylation and dioxygenation of indoles via electron donor–acceptor complexes

Abstract

A photoresponsive electron donor-acceptor (EDA) complex, formed by indole and hypervalent iodine such as diacetoxyiodobenzene (DAIB/PIDA, etc.) was detectable through absorption and emission spectroscopy. Irradiation of the EDA complex with...

Acetoxy Group-Directed Regioselective C2 Alkenylation of Indoles via Pd–Ag Bimetallic Catalysis

“…All of the commercially available starting materials, reagents, and catalysts were utilized without further purification. A previously reported procedure synthesized the starting 3-acetoxyindoles . All reactions were monitored by thin layer chromatography (TLC) on a Merck silica gel 60 F 254 precoated silica plate.…”

“…A previously reported procedure synthesized the starting 3-acetoxyindoles. 30 All reactions were monitored by thin layer chromatography (TLC) on a Merck silica gel 60 F 254 precoated silica plate. The TLC plates were visualized under UV irradiation using a wavelength of 254 nm or strained using a vanillin stain solution followed by heating with a heat gun.…”

Photo-induced 1,2-alkylarylation/cyclization of alkenes, alkyl halides and N-alkylindoles via an EDA-complex

“…The organo-photocatalytic strategy, which did not require external photosensitizers, relied upon the formation of photoactive electron donor–acceptor complex (EDA) 10 or charge-transfer complex (CTC). 11 However, due to the problems associated with unproductive, fast, and reversible electron transfer from the donor to the acceptor, the EDA complex-enabled synthetic chemistry is limited and mainly focusing on the direct cross-coupling, 12 reductive reactions, 13 annulations 14 under metal-/photocatalyst-free conditions. In contrast, visible light driven the multi-component reactions, especially involving C–H activation, to build high-value-added products with high selectivity and efficiency are still worth exploring.…”

A transition metal- and photosensitizer-free approach for site-selective (hetero)arylation of polychlorinated heteroarenes

“…Herein, we present our findings of a novel photochemical method for the selective C(sp 2 )–X/C(sp 2 )–H cross-coupling of polychlorinated heteroarenes with indole derivatives or electron-rich arenes. Our approach relies on in situ generation of unconventional electron donor–acceptor (EDA) complexes 23,24 originating from two substrates and a basic additive, namely heteroarene-indole anion-cesium cation complexes (Scheme 1c). The controlled single electron transfer (SET) process occurring in these EDA complexes, followed by the combination of resulting radical species, permits high reaction efficiency and site-selectivity in the formation of biaryl heterocyclic compounds without the need for transition metal catalysts or external photosensitizers.…”