电化学条件下以羧酸铵为酰氧基源的吲哚直接酰氧基化反应

doi:10.6023/cjoc202604023

摘要/Abstract

电化学条件下吲哚的官能团化反应是构建吲哚衍生物的一种高效绿色的方法. 本工作首次报道了一种新型的电化学条件下2-芳基吲哚C3位酰氧基化反应. 该反应使用四丁基羧酸铵盐作为酰氧基源和电解质, 在无催化剂和氧化剂的条件下, 以中等至优异的产率生成了酰氧基化的吲哚产物. 根据机理研究结果, 提出反应是通过吲哚阳极氧化形成自由基阳离子, 然后与羧酸负离子直接偶联的步骤进行. 该反应条件温和, 反应底物适用性广, 为合成3-酰氧基吲哚提供了一种新型的绿色的策略.

关键词: 2-芳基吲哚, 酰氧基化, 电化学反应, 自由基反应, 四丁基乙酸铵

Electrochemical functionalization of indoles represents an efficient and green strategy for the synthesis of indole derivatives. Herein, we report for the first time an electrochemical C3 acyloxylation reaction of 2-arylindoles. This radical acyloxylation reaction uses tetrabutylammonium carboxylates as both the acyloxy sources and the electrolytes, affording acyloxylated indoles as products in moderate to excellent yields under catalyst- and oxidant-free conditions. Mechanistic studies disclose that this reaction proceeds via anodic oxidation of the indole to form a radical cation, followed by direct coupling with a carboxylate anion and subsequent deprotonation. The transformation features mild conditions, broad substrate scope, and scale-up applicability, which provides a new and green strategy for the synthesis of 3-acyloxyindoles.

Key words: 2-arylindoles, acyloxylation, electrochemical reaction, radical reaction, tetrabutylammonium acetate

引用此文

赫景瑞, 王蕴歆, 梅海波, 韩建林. 电化学条件下以羧酸铵为酰氧基源的吲哚直接酰氧基化反应[J]. 有机化学, 2026, 46(9): 3578-3586.

Jingrui He, Yunxin Wang, Haibo Mei, Jianlin Han. Electrochemical Direct Acyloxylation of Indoles with Ammonium Carboxylates as Acyloxyl Sources[J]. Chinese Journal of Organic Chemistry, 2026, 46(9): 3578-3586.

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Entry	2/equiv.	Electrode	Solvent	Time/h	Temperature/℃	Current/mA	Yield^b/%
1	1.5	Pt/Pt	MeCN	5	60	5	22
2	1.5	Pt/Ni	MeCN	5	60	5	26
3	1.5	C/C	MeCN	5	60	5	26
4	1.5	C/Ni	MeCN	5	60	5	52
5	1.5	C/Pt	MeCN	5	60	5	65
6	1.5	C/SS	MeCN	5	60	5	55
7	1.5	C/Zn	MeCN	5	60	5	64
8	1.5	C/Pt	MeCN	5	60	5	37 ^c
9	1.2	C/Pt	MeCN	5	60	5	51
10	2	C/Pt	MeCN	5	60	5	58
11	3	C/Pt	MeCN	5	60	5	63
12	1.5	C/Pt	MeCN	5	80	5	55
13	1.5	C/Pt	MeCN	5	r.t.	5	54
14	1.5	C/Pt	1,4-dioxane	5	60	5	Trace
15	1.5	C/Pt	DMF	5	60	5	71
16	1.5	C/Pt	EtOH	5	60	5	Trace
17	1.5	C/Pt	DCE	5	60	5	Trace
18	1.5	C/Pt	DMSO	5	60	5	70
19	1.5	C/Pt	DMA	5	60	5	58
20	1.5	C/Pt	DMF	7	60	3	80
21	1.5	C/Pt	DMF	3	60	10	56

Entry	2/equiv.	Electrode	Solvent	Time/h	Temperature/℃	Current/mA	Yield^b/%
1	1.5	Pt/Pt	MeCN	5	60	5	22
2	1.5	Pt/Ni	MeCN	5	60	5	26
3	1.5	C/C	MeCN	5	60	5	26
4	1.5	C/Ni	MeCN	5	60	5	52
5	1.5	C/Pt	MeCN	5	60	5	65
6	1.5	C/SS	MeCN	5	60	5	55
7	1.5	C/Zn	MeCN	5	60	5	64
8	1.5	C/Pt	MeCN	5	60	5	37 ^c
9	1.2	C/Pt	MeCN	5	60	5	51
10	2	C/Pt	MeCN	5	60	5	58
11	3	C/Pt	MeCN	5	60	5	63
12	1.5	C/Pt	MeCN	5	80	5	55
13	1.5	C/Pt	MeCN	5	r.t.	5	54
14	1.5	C/Pt	1,4-dioxane	5	60	5	Trace
15	1.5	C/Pt	DMF	5	60	5	71
16	1.5	C/Pt	EtOH	5	60	5	Trace
17	1.5	C/Pt	DCE	5	60	5	Trace
18	1.5	C/Pt	DMSO	5	60	5	70
19	1.5	C/Pt	DMA	5	60	5	58
20	1.5	C/Pt	DMF	7	60	3	80
21	1.5	C/Pt	DMF	3	60	10	56