96747-12-5Relevant articles and documents
Copper catalyzed photoredox synthesis of α-keto esters, quinoxaline, and naphthoquinone: Controlled oxidation of terminal alkynes to glyoxals
Das, Deb Kumar,Kumar Pampana, V. Kishore,Hwang, Kuo Chu
, p. 7318 - 7326 (2018/10/15)
Herein, we report a facile visible light induced copper catalyzed controlled oxidation of terminal CC alkynes to α-keto esters and quinoxalines via formation of phenylglyoxals as stable intermediates, under mild conditions by using molecular O2 as a sustainable oxidant. The current copper catalysed photoredox method is simple, highly functional group compatible with a broad range of electron rich and electron poor aromatic alkynes as well as aliphatic alcohols (1°, 2° and 3° alcohols), providing an efficient route for the preparation of α-keto esters (43 examples), quinoxaline and naphthoquinone with higher yields than those in the literature reported thermal processes. Furthermore, the synthetic utility of the products has been demonstrated in the synthesis of two biologically active molecules, an E. coli DHPS inhibitor and CFTR activator, using the current photoredox process. In addition, we applied this methodology to the one-pot synthesis of a heterocyclic compound (quinoxaline, an FLT3 inhibitor) by trapping the intermediate phenylglyoxal with O-phenylenediamine. The intermediate phenylglyoxal can also be isolated and further reacted with an internal alkyne to form naphthoquinone. This process can be readily scaled up to the gram scale.
Photochemical Reactions of Mercapto/Amino Substituted Alkyl Phenylglyoxylates Induced by Intramolecular Electron Transfer
Hu, Shengkui,Neckers, Douglas C.
, p. 2751 - 2766 (2007/10/03)
2'-Alyothio ethyl phenylglyoxylates (1) and 2'-dimethylamino ethyl phenylglyoxylate (10) were synthesized and their photochemistry studied.In contrast to their oxygen analog 3, which give normal Norrish type II cleavage products, the title compounds undergo intermolecular electron transfer from the heteroatom (sulfur/nitrogen) to the excited carbonyl group, followed by proton transfer and subsequent closing of the resulting biradical to produce seven-mebered (11) lactones in high yield.Thiadialkyl phenylglyoxylates (9) react inefficiently due to intramolecular self-quenching of phenylgluoxylate chromophores.The photoreactivity of α-oxothioester (14) was compared with that of its nitrogen (α-oxoamide) and oxygen (phenylglyoxylate) counterparts. - Keywords: Photochemical; Mercapto; Amino; Phenylglyoxylates; Electron Transfer
