Table 2.

Preparation of 3-Sulfenyl- and 3-Selenylindoles by n-Bu₄NI-Induced Electrophilic Cyclization^a

entry	1	R1	R2	R3	ArSCl/ArSeCl	time (h)	3	% yieldb
1	1a	Me	C6H5	H	p-O2NC6 H5SCl	5	3a	90
2	1a	Me	C6H5	H	F5C6 SCl	5	3b	87
3	1a	Me	C6H5	H	C6H5 SCl	6	3c	87
4	1a	Me	C6H5	H	p-MeC6 H5SCl	6	3d	92
5	1a	Me	C6H5	H	o-O2NC6 H5SCl	5	3e	52
6	1a	Me	C6H5	H	C6H5SeCl	5	3f	84
7	1b	Me	C6H5	6-Me	p-O2NC6 H5SCl	9	3g	78
8	1c	Me	C6H5	5-Br	p-O2NC6 H5SCl	6	3h	85
9	1d	Me	C6H5	5-CO2Me	C6H5 SCl	8	3i	75
10	1e	Me		H	p-O2NC6 H5SCl	9	3j	74
11	1f	Me		H	p-O2NC6 H5SCl	3	3k	85
12	1g	Me		H	p-O2NC6 H5SCl	3	3l	91
13	1h	Me		H	C6H5 SCl	4	3m	79
14	1i	C6H5		H	p-MeC6 H5SCl	3	3n	99

^aRepresentative procedure: N,N-dialkyl-2-(1-alkynyl)aniline1 (0.50 mmol), n-Bu₄NI (0.50 mmol), arylsulfenyl/arylselenenyl chloride (1.00 mmol), and 5 mL of DCE were mixed in a sealed 4-dram vial. The reaction was stirred at 70 °C for the indicated time.

^bIsolated yields after column chromatography.