Visible-Light-Induced C(sp²)–C(sp³) Cross-Dehydrogenative-Coupling Reaction of N-Heterocycles with N-Alkyl-N-methylanilines under Mild Conditions

Abstract

Disclosed herein is a cross-dehydrogenative-coupling reaction of N-heterocycles including 1,2,4-triazine-3,5(2H, 4H)-diones and quinoxaline-2(1H)-ones with N-methylanilines to form C(sp 2 )−C(sp 3 ) under visible-light illumination and ambient air at room temperature. In this process, easily available Ru(bpy) 3 Cl 2 •6H 2 O serves as the catalyst, and air acts as the green oxidant. This method features high atom economy, environmental friendliness, and convenient operation and provides an efficient and practical access to aminomethyl-substituted Nheterocycles with extensive functional group compatibility in 40− 86% yields.

Visible-Light-Induced Oxyalkylation of 1,2,4-Triazine-3,5(2H, 4H)-diones with Ethers via Oxidative Cross-Dehydrogenative Coupling

“…The substrates of various 1,2,4-triazine-3,5­(2 H , 4 H )-diones ( 1a - 1ad , 1ar ) involved in Schemes and were synthesized according to procedures described in the previous literature, and the spectral characteristics data were consistent with those reported previously in the literature. , …”

“…The substrates of various 1,2,4-triazine-3,5(2H, 4H)diones (1a-1ad, 1ar) involved in Schemes 2 and 3 were synthesized according to procedures described in the previous literature, and the spectral characteristics data were consistent with those reported previously in the literature. 7,8 General Procedure for the Cross-Dehydrogenative Coupling of 1,2,4-Triazine-3,5(2H, 4H)-diones with Ethers (Condition A for 3a− 3am, 3aq−3ar). An oven-dried Schlenk tube was charged with 1,2,4triazine-3,5(2H, 4H)-diones (1) (0.3 mmol), 2-tert-butylanthraquinone (0.03 equiv, 0.009 mmol), Cs 2 CO 3 (0.5 equiv, 0.15 mmol), and a magnetic stirring bar.…”

“…In 2021, the Kim group disclosed an elegant C–H alkylation of 1,2,4-triazine-3,5­(2 H , 4 H )-diones with sulfur ylides in good yields (Scheme c) . Recently, our group reported a visible-light-induced cross-dehydrogenative-coupling reaction of 1,2,4-triazine-3,5­(2 H , 4 H )-diones and with N -methylanilines (Scheme c) . On the other hand, direct radical coupling α-C–H of ethers has emerged as one of the most versatile tools to construct a wide variety of α-substituted ether derivatives, and many meaningful accomplishments have been made in this field .…”

“…7 Recently, our group reported a visiblelight-induced cross-dehydrogenative-coupling reaction of 1,2,4triazine-3,5(2H, 4H)-diones and with N-methylanilines (Scheme 1c). 8 On the other hand, direct radical coupling α-C−H of ethers has emerged as one of the most versatile tools to construct a wide variety of α-substituted ether derivatives, and many meaningful accomplishments have been made in this field. 9 However, most of these approaches required transition metals as catalysts and stoichiometric explosive peroxides as oxidants at high temperatures.…”