S 1

Catalyst-free synthesis of 3-(1-arylsulfonylalkyl)indoles via three-component

reaction of indoles, carbonyls, and arenesulfinic acids

Wenzhong Huang†, Juan Yang†, Xiangguang Li†, Lin Yuan†, Yinhai Ma†, Qinglong Zhou†,‡,

Deqiang Liang*,†

†Department of Chemistry, Kunming University, Kunming 650214, China

‡Ruichang No.1 Middle School, Ruichang 332200, China

Email: ldq5871@126.com

Supplemental Materials

I. General

All chemicals were purchased from commercial sources and used without treatment, unless

otherwise indicated. 1H NMR and 13C NMR spectra were recorded at 25 °C on a Bruker Avance

II-400 spectrometer. High-resolution mass spectra (HRMS) were obtained using a Bruker

MicroTOF II Focus spectrometer (electrospray ionization, ESI). Thin-layer chromatography

(TLC) was carried out using silica gel GF254 plates. Melting points were uncorrected.

II. Synthesis of sulfones 4

General procedure (4a as example): A 25-mL flask was charged with a magnetic stirring bar

and p-toluenesulfinic acid 3a (312 mg, 2.0 mmol), followed by addition of CH2Cl2 (5.0 mL).

After the mixture had been stirred for 1 min to fully dissolve 3a, 1H-indole 1a (117 mg, 1.0

mmol) and benzaldehyde 2a (0.112 mL, 1.1 mmol) were added, and the resulting solution was

stirred at room temperature for 1 h. After 1a was consumed, as indicated by TLC, the reaction

mixture was quenched with saturated aqueous K2CO3 solution (20.0 mL), and extracted with

CH2Cl2 four times. The solvent of the extract was removed, and the residue was purified by

column chromatography (silica gel, petroleum ether–dichloromethane–ethyl acetate = 8:1:1, v/v)

to afford sulfone 4a as a pink solid (329 mg, 91% yield).

S 2

III. Reaction of bisindole Ia with sulfinic acid 3a

A 25-mL flask was charged with a magnetic stirring bar and p-toluenesulfinic acid 3a (312

mg, 2.0 mmol), followed by addition of CH2Cl2 (5.0 mL). After the mixture had been stirred for

1 min to fully dissolve 3a, 3,3'-(phenylmethylene)bisindole Ia (322 mg, 1.0 mmol) was added,

and the resulting solution was stirred at room temperature for 1 h. After Ia was consumed, as

indicated by TLC, the reaction mixture was quenched with saturated aqueous K2CO3 solution

(20.0 mL), and extracted with CH2Cl2 four times. The solvent of the extract was removed, and

the residue was purified by column chromatography (silica gel, petroleum ether–

dichloromethane–ethyl acetate = 8:1:1, v/v) to afford sulfone 4a as a pink solid (340 mg, 94%

yield).

S 3

Figure S 1: 1H NMR of 4d

Figure S 2: 13C NMR of 4d

S 4

Figure S 3: 1H NMR of 4f

Figure S 4: 13C NMR of 4f

S 5

Figure S 5: 1H NMR of 4g

Figure S 6: 13C NMR of 4g

S 6

Figure S 7: 1H NMR of 4h

Figure S 8: 13C NMR of 4h

S 7

Figure S 9: 1H NMR of 4i

Figure S 10: 13C NMR of 4i

S 8

Figure S 11: 1H NMR of 4m

Figure S 12: 13C NMR of 4m

S 9

Figure S 13: 1H NMR of 4n

Figure S 14: 13C NMR of 4n

S 10

Figure S 15: 1H NMR of 4r

Figure S 16: 13C NMR of 4r

S 11

Figure S 17: 1H NMR of 4s

Figure S 18: 13C NMR of 4s

S 12

Figure S 19: 1H NMR of 4t

Figure S 20: 13C NMR of 4t

S 13

Figure S 21: 1H NMR of 4u

Figure S 22: 13C NMR of 4u

S 14

Figure S 23: 1H NMR of 4v

Figure S 24: 13C NMR of 4v