Electrochemically dehydrogenative C–H/P–H cross-coupling: effective synthesis of phosphonated quinoxalin-2(1H)-ones and xanthenes

Abstract

An efficient electrochemical approach for the C(sp2)–H phosphonation of quinoxalin-2(1H)-ones and C(sp3)–H phosphonation of xanthenes has been developed.

Recent Advances in the Construction of Phosphorus‐Substituted Heterocycles, 2009–2019

“…As demonstrated in the work by the Zeng group, phosphonated quinoxalin‐2(1 H )‐ones have been also achieved through an efficient electrochemical CDC reaction of quinoxalin‐2(1 H )‐ones 110 with P(O)−H species under mild reaction conditions (Scheme ). The anodic oxidation of quinoxaline‐2(1 H )‐one 110a afforded intermediate 119 , which might then undergo electron transfer with the P(O)−H species to generate a phosphorus‐centered radical 35a .…”

“…The electrochemical oxidative C( sp 2 )−H phosphorylation of quinoxalin‐2(1 H )‐ones developed by Zeng could be also applied to xanthenes by using H ‐phosphonates or Ph 2 P(O)H, and moderate yields were obtained for products 122 (Scheme ).…”

Electrochemical Phosphorylation of Organic Molecules

“…This methodology was extended by Sun's group in the same year. [46] In addition to diaryl phenyl oxide, the authors preceded the reaction with alkylphosphonate such as dimethyl phosphonate, diethyl phosphonate, etc. The desired products were obtained with yield up to 99 %.…”

The C3-H Bond Functionalization of Quinoxalin-2(1H)-Ones With Hypervalent Iodine(III) Reagents

“…Some bioactive molecules containing quinoxalin-2(1 H )-one skeleton, such as Compounds 1 - 3 , also show potential applications in medicinal chemistry fields (Meyer et al, 2006 ; Khattab et al, 2015 ; Qin et al, 2015 ) ( Figure 1A ). Because of their synthetic usefulness and potential biological importance, the introduction of functional groups into the C3-position of the quinoxalin-2(1 H )-ones has already become a research hotspot, and various protocols for the direct C3-H functionalization of quinoxalin-2(1 H )-ones have been reported (Ebersol et al, 2019 ; Gu et al, 2019 ; Hong et al, 2019 ; Li et al, 2019 ; Peng et al, 2019 ; Rostoll-Berenguer et al, 2019 ; Teng et al, 2019 ; Wang et al, 2019a , 2020 ; Xie et al, 2019b ; Zhao et al, 2019 ; Zheng and Studer, 2019 ; Tian et al, 2020 ; Yuan et al, 2020 ). In particular, the C3-H functionalization of quinoxalin-2(1 H )-ones involving hypervalent iodine reagents has drawn wide attention for the aforementioned advantages of hypervalent iodine reagents, mainly including arylation (Paul et al, 2017 ; Yin and Zhang, 2017 ), trifluoromethylation (Wang et al, 2018 ; Xue et al, 2019a ), alkylation (Wang et al, 2019b ; Xie et al, 2019a ; Xue et al, 2019b ; Shen et al, 2020 ), and alkoxylation (Xu et al, 2019 ; Yang et al, 2019 ) of quinoxalin-2(1 H )-ones, which provide convenient and environmentally friendly means for the synthesis of 3-substituted quinoxalinone derivatives.…”