Visible-Light-Driven Epoxyacylation and Hydroacylation of Olefins Using Methylene Blue/Persulfate System in Water

Abstract

A visible-light-driven strategy for hydroacylation and epoxyacylation of olefins in water using methylene blue as photoredox catalyst and persulfate as oxidant is reported. In this unprecedented unified approach, two different transformations are accomplished using only one set of reagents. The method has a broad scope spanning a range of aromatic and aliphatic aldehydes as well as conjugated and nonconjugated olefins to deliver ketones and epoxyketones from abundant and inexpensive chemical feedstocks.

Radical Carbonylative Synthesis of Heterocycles by Visible Light Photoredox Catalysis

“…The group of Salles Jr achieved the same reaction in water with the use of persulfate K2S2O8 as the oxidant and methylene blue as the organophotoredox catalyst (Scheme 12) [55]. It is noteworthy that O2 in water plays an important role in this transformation.…”

Acyl Radical Chemistry via Visible-Light Photoredox Catalysis

“…Epoxyacylation and hydroacylation using methylene blue as the photocatalyst and persulfate as the oxidant. 40 …”

“…Salles et al , in 2018, achieved acyl-epoxylation and hydroacylation of alkenes using methylene blue (MB) as a photoredox catalyst and K 2 S 2 O 8 as an oxidant in air-equilibrated water solution (Scheme 26). 40 With high loading of the photocatalyst and oxidant (2.50 mol% and 2.00 equiv, respectively), simple benzaldehydes with arene substituted with methyl, Cl, F, MeO or CF 3 reacted with styrenes or 2-vinylpyridine to afford the desired epoxide products in 75% to 92%. 1-Naphthaldehyde and cyclohexanecarboxyaldehyde were also viable substrates forming the final products in 84% and 79% yields.…”

One Pot and Two Pot Synthetic Strategies and Biological Applications of Epoxy-Chalcones

“…Epoxy chalcone has also been prepared via metal and metal-free catalyzed oxidative cross coupling of alkenes with aldehyde (route ii) in the presence of various catalysts such as NHC/NBS/1,8-diazabicyclo [5.4.0]undec-7-ene (DBU) [39], Ru(bpy) 3 Cl 2 /t-BuOOH/Cs 2 CO 3 [40], proline based organocatalyst [41], mesoporous zeolite ETS-10 (METS-10)/tert-butyl hydrogen peroxide (TBHP) [42], TBHP/t-BuOK [43], Cu, Fe, Ni, Co-doped zeolite X [44], methylene blue/K 2 S 2 O 8 [45] and FeCl 2 /DBU [46]. The synthesis of α-β-epoxy ketones have also been reported using C-H activation and decarboxylative cross coupling of methyl arenes with cinnamic acid in the presence of MnO 2 /TBHP (route iii) [47] and photoxidative aerobic reaction of benzyl alcohol with styrene under iodine (route iv) [48].…”