Chemoenzymatic cascade reaction as a sustainable and scalable access to para-quinols

Abstract

A novel protocol for the synthesis of para-quinols from inexpensive phenols based on chemoenzymatic casade reaction is reported. Protocol combines an enzymatic oxidation of hydroquinones to benzoquinones and their transformation...

The Influence of Ligands on the Pd-Catalyzed Diarylation of Vinyl Esters

“…, 29, x FOR PEER REVIEW 3 of 9 Based on the previously obtained data [6], the studied reaction led to the formation of 1,2-diphenylethyl acetate (3) as a main product and two by-products-stilbene (4) and 2-phenyl-1,4-benzoquinone (5). The majority of the re-oxidant-benzoquinone-was reduced to hydroquinone, which remains in a water phase after the extraction of reaction products by ethyl acetate.…”

“…2-phenyl-1,4-benzoquinone (5). The product was isolated as a brown solid from a silica column eluted by EtOAc/hexanes (30:70); 1 H NMR (400 MHz, CDCl 3 ): δ 7.49-7.42 (m, 5H), 6.87-6.80 (m, 3H); 13 C{H} NMR (100 MHz, CDCl 3 ): δ 187.6, 186.6, 145.9, 137.0, 136.2, 132.2, 130.1, 129.2, 128.5.…”

“…Our ongoing interest in the design of environmentally benign protocols for the synthesis of biologically relevant compounds [4,5] led us to the development of a palladiumcatalyzed 1,2-diarylation of vinyl esters in an aqueous medium [6]. This protocol utilizes arylboronic acids and inexpensive palladium acetate as a catalyst and offers ready-made one-step access to 1,2-diarylethyl esters.…”

One-pot chemo- and photo-enzymatic linear cascade processes

“…However, the method suffers from a low atom economy and is limited to benzoquinone derivatives. To overcome these drawbacks, the authors envisioned 142 a chemo-enzymatic approach that combines laccase-catalysed in situ oxidation of hydroquinones to the corresponding quinones with subsequent CuI-catalysed C–C coupling with arylboronic acids in a concurrent mode (Scheme 27). After optimization of the reaction conditions, the synthetic applicability was shown for a wide spectrum of p -quinol derivatives that were obtained in yields higher than or similar to those obtained from quinones.…”