Synthesis of substituted dihydrothiophenes 2a–2n^a.

Entry	Compd	Ar	R	Yield (%)b
1	2a	p-CH3OC6H4	Me	68
2	2b	m-NO2C6H4	Me	55
3	2c	p-CH3C6H4	CH2OH	63
4	2d	p-CH3OC6H4	Sec-Bu	68
5	2e	p-CH3C6H4	Sec-Bu	64
6	2f	C6H5	Bn	48
7	2g	p-CH3OC6H4	Bn	62 (53 : 47)
8	2h	m-CH3OC6H4	Bn	60 (51 : 49)
9	2i	o-CH3OC6H4	Bn	56 (51 : 49)
10	2j	p-CH3C6H4	Bn	55 (52 : 48)
11	2k	p-ClC6H4	Bn	53 (53 : 47)
12	2l	p-BrC6H4	Bn	55 (53 : 47)
13	2m	p-CH3OC6H4	CH2CH2Ph	67 (54 : 46)
14	2n	p-CH3OC6H4	CH2C6H5OH-p	57 (55 : 45)

^aReaction conditions: ArCHO (2.0 mmol), CH₂(CN)₂ (2.0 mmol), α-amino acid ethyl esters (2.0 mmol), 1,3-thiazolidinedione (2.0 mmol), Et₃N (3.0 mmol), 40–50 °C, 6 h.

^bIsolated yields.