Table 3. Investigation of substrate scope for the SGP-catalysed asymmetric Mannich reaction^a.

Entry	X	R1	R2	Product No.	Time (h)	Yield (%)b	dr (syn:anti)c	e.e. (syn) (%)d
1	CH2	4-NO2C6H4	H	4a	96	64	88:12	83
2	CH2	4-CF3C6H4	H	4b	94	73	81:19	78
3	CH2	4-BrC6H4	H	4c	94	65	74:26	76
4	CH2	4-ClC6H4	H	4d	120	92	78:22	75
5	CH2	3-FC6H4	H	4e	94	72	70:30	74
6	CH2	4-FC6H4	H	4f	94	66	66:34	64
7	CH2	4-CNC6H4	H	4g	120	61	58:42	68
8	CH2	C6H5	H	4h	100	62	60:40	61
9	CH2	4-CH3C6H4	H	4i	120	68	40:60	33
10	CH2	4-NO2C6H4	3-Br	4j	144	24	92:8	88
11	CH2	4-NO2C6H4	3-CH3	4k	123	54	91:9	83
12	CH2	4-NO2C6H4	4-Cl	4l	144	47	89:11	83
13	CH2	4-NO2C6H4	4-CH3	4m	120	81	90:10	82
14	CH2	4-NO2C6H4	4-OCH3	4n	117	71	72:28	72
15	CH2	4-BrC6H4	4-OCH3	4o	165	66	52:48	40
16e	S	4-ClC6H4	H	4p	168	81	57:43	58
17e	S	4-CF3C6H4	H	4q	142	80	44:56	52

^aReaction conditions: a mixture of aromatic aldehyde (0.5 mmol), arylamine (0.55 mmol), ketone (7.5 mmol), deionised water (0.10 mL), MeCN (0.9 mL) and SGP (50 mg) was stirred at 30°C.

^bYield of the isolated product after silica gel chromatography.

^cDetermined by chiral HPLC analysis.

^de.e. value of the syn-isomer, determined by chiral HPLC; the absolute configuration was assigned by comparison with the literature (for details, please see the Supplementary Information).

^etetrahydrothiopyran-4-one (1 mmol).