Table 1.

Optimization of aldol reactions using method A^a

entry	compd	base	solvent	diastereoselectivityb
1	4a	Et3N	CH2Cl2	78:7:6:9 (rt)
2	4a	Et3N	CH2Cl2	80:12:4:4
3	4c	Et3N	CH2Cl2	78:4:16:2 (rt)
4	4e	Et3N	CH2Cl2	72:9:10:9 (rt)
5	4f	Et3N	CH2Cl2	57:27:16 (rt)c
6	4g	Et3N	CH2Cl2	31:16:53 (rt)c
7	4a	BuNH2	CH2Cl2	trace product
8	4a	PhNH2	CH2Cl2	no product
9	4a	i-Pr2NH	CH2Cl2	73:15:4:8
10	4a	DIPEAd	CH2Cl2	no product
11	4a	pyridine	CH2Cl2	no product
12	4a	DBUe	CH2Cl2	no product
13	4a	Et3N	ClCH2CH2Cl	72:16:7:5
14	4a	Et3N	EtOAc	76:7:8:9
15	4a	Et3N	THF	71:2:7:20
16	4a	Et3N	Et2O	64:6:14:16
17	4a	Et3N	toluene	57:6:6:31
18	4a	Et3N	CH3CN	no product

^aUnless indicated, all reactions were carried out at 0 °C;

^bDiastereoselectivity was determined by HPLC. See SI for details;

^cDiastereomers were inseparable under this HPLC condition;

^dDiisopropylethylamine;

^e1,8-Diazabicyclo[5.4.0]undec-7-ene.