Table 3.

Scope of the ketone aldol/cyclization reaction with isocyanoacetates.

Entry	2	3	R1	R2	4	Yield [%][a]	d.r.[b]	e.r.[c]
1	2 a	3 a	Ph	Me	4 a	84	94:6	94:6
2	2 a	3 b	p-CH3OC6H4	Me	4 b	73	92:8	94:6
3	2 a	3 c	5-Br-thiophen-2-yl	Me	4 c	78	88:12	93:7
4	2 a	3 d	p-NO2C6H4	Me	4 d	60	90:10	95:5
5	2 a	3 e	p-BrC6H4	Me	4 e	71	89:11	95:5
6	2 a	3 f	p-CNC6H4	Me	4 f	80	90:10	96:4
7	2 a	3 g	4-F,3-BrC6H3	Me	4 g	83	85:15	89:11
8	2 a	3 h	3,5-(CF3)2C6H3	Me	4 h	82	86:14	88:12
9	2 a	3 i	5-methylthiazol-2-yl	Me	4 i	55	91:9	93:7
10	2 a	3 j	pyrazin-2-yl	Me	4 j	75	91:9	91:9
11	2 a	3 k	Ph	Et	4 k	76	90:10	99:1
12	2 a	3 l	p-MeC6H4	Et	4 l	81	91:9	98:2
13	2 a	3 m	p-FC6H4	Et	4 m	83	88:12	99:1
14	2 a	3 n	p-BrC6H4	Et	4 n	73	90:10	99:1
15	2 a	3 o	Ph	Pr	4 o	79	87:13	99:1
16	2 a	3 p	2-thienyl	Pr	4 p	81	84:16	96:4
17	2 a	3 q	Ph	CH2iPr	4 q	75	96:4	97:3
18	2 b	3 k	Ph	Et	4 r	81	90:10	99:1
19	2 b	3 l	p-MeC6H4	Et	4 s	82	91:9	98:2
20	2 c	3 k	Ph	Et	4 t	77	91:9	99:1

^[a]Combined yield of both diastereomers after flash column chromatography.

^[b]Determined by ¹HNMR analysis of the crude reaction mixture.

^[c]Determined by HPLC analysis on a chiral stationary phase.