Table 2. Synthesis of Thienoindole 4 by Cascade Reaction of Indoline-2-thione 1 with Hydrazinonitroalkene 2^a.

entry	1, R	2, Ar	R1	3 or 4	time	% yieldb
1	1a, Me	2a, 4-MeC6H4	iPr	4a	4 d	78
2	1a, Me	2b, C6H5	iPr	4b	4 d	58
3	1a, Me	2c, 4-OMeC6H4	iPr	4c	2 d	66
4	1a, Me	2d, 4-OMeC6H4	tBu	4d	3 d	75
5	1a, Me	2e, 4-ClC6H4	iPr	4e	3 d	66
6	1a, Me	2f, 2-thienyl	iPr	4f	3 d	40c
7	1b, Et	2a, 4-MeC6H4	iPr	4g	8 d	43c
8	1c, nPr	2a, 4-MeC6H4	iPr	4h	7 d	65
9	1d, Bn	2a, 4-MeC6H4	iPr	4i	8 d	64
10	1a, Me	2a, 4-MeC6H4	iPr	3a	3 h	46d
11	1a, Me	2g, Cy	iPr	4j	1 d	e

^aReaction scale: 1 (0.7 mmol, 1.0 equiv), 2 (0.7 mmol, 1.0 equiv), KOAc (0.7 mmol, 1.0 equiv), and acetic acid (0.4 μL, 1 mol %) in CH₃CN (3 mL) at RT.

^bAfter silica gel column chromatography.

^c10–20% of 1 and 2 was recovered; prolonged reaction led to a complex mixture.

^dShort reaction time allows isolation of the product before aromatization in this case.

^eComplex mixture.