16459-09-9

Upstream product

• 30877-08-8 1,2-diphenylnaphthalene 
• 98-86-2 acetophenone 
• 1074-12-0 phenylglyoxal hydrate 
• 501-65-5 diphenyl acetylene 
• 51670-54-3 Diphenyl-acetic acid 3,4-diphenyl-naphthalen-1-yl ester 
• 51314-29-5 3,4-diphenylnaphthalen-1-ol 

Downstream Products

• 1684-07-7 3,4-diphenyl-isochromen-1-one 

Relevant academic research and scientific papers

Copper catalyzed photoredox synthesis of α-keto esters, quinoxaline, and naphthoquinone: Controlled oxidation of terminal alkynes to glyoxals

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.

Rapid, Operationally Simple, and Metal-free NBS Mediated One-pot Synthesis of 1,2-Naphthoquinone from 2-Naphthol

A metal-free, one-pot synthesis of 1,2-naphthoquinone was accomplished from 2-naphthol by utilizing economically cheap NBS under open air conditions. Initial formation of 1,1-dibromonaphthalen-2-one and subsequent transformation afforded the 1,2-naphthoquinone. This oxidation was completed within 30 min and had broad substrate scope. Moreover, this system tolerated heterocyclic systems and was also applicable to 1,3-dicarbonyl systems. This practical approach with short reaction times, a simple workup, and insensitivity to moisture could override the usage of expensive and hazardous oxidizing and metal reagents. (Figure presented.).

Rhodium(I)-Catalyzed Decarbonylative Aerobic Oxidation of Cyclic α-Diketones: A Regioselective Single Carbon Extrusion Strategy

A rhodium-catalyzed decarbonylative aerobic oxidation of cyclic α-diketones has been developed for the first time, where the regioselective formations of α-pyrones and isocoumarins have been achieved. The current decarbonylative aerobic oxidation pathway proceeds via the C-C bond cleavage followed by a C-O bond formation, representing a biomimetic oxidation approach to unsaturated six-membered cyclic lactones. The unique ability of rhodium catalysts to induce the decarbonylative aerobic oxidation opens up a new synthetic toolbox that utilizes the "regioselective single carbon" extrusion strategy.

Experimental and Theoretical Studies on Iron-Promoted Oxidative Annulation of Arylglyoxal with Alkyne: Unusual Addition and Migration on the Aryl Ring

An Fe(III)-promoted oxidative annulation reaction was developed for the synthesis of 1,2-naphthoquinones. A variety of substituted arylglyoxals and internal alkynes undergo the transformation in the presence of FeCl3 at room temperature to afford the 1,2-naphthoquinone products in good yields in a short reaction time. Interestingly, the products show unusual pseudomigration of the substituent on the arene ring of arylglyoxals. A possible mechanism involving Fe(III)-promoted formation of a vinyl cation from arylglyoxal and alkyne, electrophilic addition of the vinyl cation to the ipso carbon of the aryl group to give a spiral intermediate, and then migration of the keto carbon to the ortho carbon was proposed as key steps and verified using quantum mechanics.

Copper-catalyzed divergent oxidative pathways of 2-naphthol derivatives:: Ortho -naphthoquinones versus 2-BINOLs

Catalyst-dependent divergent pathways of 2-naphthol derivatives have been investigated. A readily available CuCl2-DMAP catalyst system promotes the aerobic oxidation of 2-naphthol derivatives to ortho-naphthoquinones whereas switching the catalyst system to Cu(OAc)2-DBN under an argon atmosphere allows the oxidative coupling of 2-naphthols to 1,1′-bi-2-naphthols (BINOLs) in good to excellent yields.