Phenyliodonium Diacetate Mediated Carbotrifluoromethylation of Quinoxalin‐2(1H)‐ones

Abstract

An efficient method for the synthesis of 3trifluoromethylquinoxalin-2(1H)-ones by a direct trifluoromethylation of quinoxalin-2(1H)-one derivatives has been developed under transition-metal-free conditions. The strategy uses cheap and commercially available PhI(OAc) 2 as a promoter, TMSCF 3 as a trifluoromethylation reagent in the presence of catalytic amount of benzoquinone to give the products in good yields.

Recent Advances in Direct C−H Trifluoromethylation of N‐Heterocycles

“…After this pioneering work of C3 trifluoromethylation on quinoxalin-2(1H)-ones with CF 3 SO 2 Na, various reports were published on the generation of this moiety. In 2019, Hu & group [26] established an oxidative CÀ H trifluoromethylation of quinoxalinones using TMSCF 3 as the trifluoromethylating reagent. They used PhI(OAc) 2 as the oxidant in the presence of a catalytic amount of benzoquinone (BQ) and KF as the additive in the argon atmosphere (Scheme 3).…”

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

“…Soon afterwards, in March 2019, Xue et al reported a method to synthesize 3-trifluoromethylquinoxalin-2(1 H )-ones with (trifluoromethyl)trimethylsilane (Ruppert-Prakash reagent) as a trifluoromethyl source under transition metal-free conditions ( Figure 1B , Equation d) (Xue et al, 2019a ). This protocol has the advantages of using cheaper (diacetoxyiodo)benzene(PhI(OAc) 2 )compared with PhI(OTFA) 2 as an oxidant and stable (trifluoromethyl)trimethylsilane as the trifluoromethyl source.…”

“…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. In this mini review, we will focus on the progress being made in the direct C3-H functionalization of quinoxalin-2(1 H )-ones involving the hypervalent iodine reagents and discuss their mechanisms, in order to inspire more applications of hypervalent iodine reagents in related reactions.…”

Hypervalent Iodine(III)‐Promoted Rapid Cascade Reaction of Quinoxalinones with Unactivated Alkenes and TMSN3

“…65,156.44,140.35,133.36,131.31,129.00,128.83,115.80,53.81,40.85,33.45,20.31,20.13,19.45,14.19. HRMS (ESI): Calculated for C 15…”

“…13 C NMR (126 MHz,CDCl 3 ) δ 159.93,154.64,133.01,132.52,130.25,130.14,123.73,113.66,53.37,41.82,33.49,32.63,29.92,29.24,25.60. HRMS (ESI): Calculated for C 15 7.59-7.54 (m, 1H), 7.38-7.34 (m, 1H), 7.32 (dd, J = 8.4, 1.4 Hz, 1H), 4.03 (t, J = 6.6 Hz, 2H), 3.86 (dd,J = 11.8,8.2 Hz,1H),3.72 (m,4H),3.60 (dd,J = 11.8,5.5 Hz, 1H), 3.07 (td, J = 8.6, 1.1 Hz, 1H), 2.26-2.18 (m, 2H), 2.15-2.12 (m, 1H), 1.96-1.83 (m, 3H), 1.70 (ddd, J = 10.6, 5.2, 2.7 Hz, 2H), 1.67-1.63 (m, 2H), 1.44-1.34 (m, 2H). 13 C NMR (126 MHz, CDCl 3 ) δ 175.…”