Table 2.

Synergism in the Arrangement of the Substituents in the Boroxinate Core.^a

entry	ligand	phenol/alcohol	catalyst	time (h)	% yield 3b	erc
1	L-4	P-3	LAP 4-5-3	36	64	57 : 43
2	L-4	P-5	LAP 4-5-5	39	86	58 : 42
3	L-4	P-6	LAP 4-5-6	24	91	58 : 42
4	L-4	P-11	LAP 4-5-11	24	76	59 : 41
5	L-4	P-13	LAP 4-5-13	36	75	59 : 41
6	L-4	P-26	LAP 4-5-26	39	82	64 : 36
7	L-4	P-28	LAP 4-5-28	39	71	60 : 40
8	L-4	P-36	LAP 4-5-36	36	72	70 : 30
9	L-1	P-36	LAP 1-5-36	39	52	49 : 51d
10	L-2	P-36	LAP 2-5-36	42	62	54 : 46
11	L-3	P-36	LAP 3-5-36	45	62	52 : 48
12	L-5	P-36	LAP 5-5-36	39	89	74 : 26
13	L-6	P-36	LAP 6-5-36	39	64	35 : 65d
14	L-7	P-36	LAP 7-5-36	39	93	74 : 26
15	L-8	P-36	LAP 8-5-36	39	94	15 : 85d
16	L-9	P-36	LAP 9-5-36	42	90	71 : 29
17	L-8	P-11	LAP 8-5-11	39	74	62 : 38e
18	L-8	P-26	LAP 8-5-26	39	93	78 : 22e

^aUnless otherwise specified, all reactions were carried out at 0.2 M in 1 (0.25 mmol) in toluene with 2.0 equiv amine and 1.5 equiv of 2 at rt for the indicated time with 20 mol% of the catalyst. The catalyst was made from the (S)-enantiomer of the ligand (≥99% ee) according to the procedure in Table 1.

^bIsolated yield after chromatography on silica gel.

^cDetermined by HPLC.

^dCatalyst generated from (R)-ligand.

^eThe ligand for this run was 97% ee.

^f The catalyst loading was 10 mol%.