Table 1. Ligand, Additive, and Solvent Screening for the Asymmetric Epoxidation^a.

entry	ligand	solvent	additive	t (h)	yield (%)b	ee (%)c
1	1	DCM	–	2.5	38	–12
2	2	DCM	–	2.5	54	37
3	3	DCM	–	2.5	69	49
4	4	DCM	–	2.5	71	41
5	5	DCM	–	2.5	84	94
6	d	DCM	–	8	traces	n.d.e
7	5	DCM	LiCl	24	81	93
8	5	DCM	LiBr	24	0	–
9	5	DCM	NaCl	2.5	91	96
10	5	DCM	LiF	2.5	92	95
11	5	DCM	Na2SO4	2.5	92	95
12	5	toluene	NaCl	24	83	93
13	5	THF	NaCl	24	49	55
14f	5	DCM	NaCl	24	51	92
15g	5	DCM	NaCl	24	73	94
16g,h	5	DCM	NaCl	8	87	95
17g,h,i	5	DCM	NaCl	3	92	95
18h,j	5	DCM	NaCl	24	62	n.d.e
19j,k	5	DCM	NaCl	24	86	79
20g,h,i,l	5	DCM	NaCl	3	89	96

^aUnless otherwise stated, reactions were performed on a 0.25 mmol scale of cis-2-hexen-1-ol (1a) using 2.0 equiv; 30% aqueous H₂O₂, 5 mol % WO₂(acac)₂, 5.5 mol % BHA ligand, and 1.0 equiv additive at rt in 5.0 mL solvent.

^bYields of isolated products.

^cDetermined by HPLC on a chiral stationary phase on the corresponding benzoate.

^d(−)-TADDOL was used as ligand.

^eNot determined.

^fWO₂Cl₂ was used instead of WO₂(acac)₂.

^g2.0 mol % WO₂(acac)₂ and 2.4 mol % BHA-5 were used.

^h0.5 equiv NaCl was used.

ⁱReaction was performed in 2.5 mL DCM.

^jReactions were performed on 1.0 mol % WO₂(acac)₂, 1.2 mol % BHA-5 in 0.5 mL DCM.

^k0.25 equiv NaCl was used.

^lThe reaction was performed on a scale of 10.0 mmol 1a.