Table 4.

Triflic acid catalyzed synthesis of N-sulfonyl carbazoles from aryl sulfonamides and 2,5-dimethoxytetrahydrofuran.^a

Entry	Ar	Time (h)	Selectivityb (%)	Yieldc (%)
1	C6H5	2	92	79
2	p-CH3C6H4	2	91	81
3	p-OCH3C6H4	2	88	75
4	p-BrC6H4	2	85	77
5	o-CH3C6H4	2	91	82
6	p-ClC6H4	2	93	86
7	p-NO2C6H4	2	85	75
8	Naphth-2-yl	2	91	82

^aReaction conditions: sulfonamide (0.636 mmol), 2,5-dimethoxytetrahydrofuran (5 eqv.), TfOH (3.5 eqv.), RT, 2h.

^bDetermined by GCMS.

^cIsolated yields after flash chromatography.