Table 1. Asymmetric Epoxidation of Methyl Cinnamate 10a^a.

entry	catalyst	yield (%)c	ee (%)d
1e	1b	66	91
2f	1c	48	95
3	Fe(3,5-diCF3iQ2dp)	99 (98)g	95
4	Fe(iQ2dp)	37	57
5	Fe(3,5-diCF3iQ2mc)	32	55
6	Fe(3,5-di-t-BuiQ2dp)	85	69
7	Fe(3,4,5-tri-FiQ2dp)	50	60
8	Fe(2,4,6-tri-iPriQ2dp)	0
9	Fe(2,4,6-tri-iPriQ2mc)	0

^aReaction conditions: H₂O₂ (1.5 equiv) in acetonitrile (0.5 M) is added over 30 min to a TFE (0.25 M) solution of alkyl cinnamate (1 equiv), catalyst (2 mol %), and benzoic acid (0.5 equiv) at −40 °C.

^bThe absolute configuration of the product was assigned as (−)-(2R,3S)-11.

^cHigh-performance liquid chromatography (HPLC) yield using chlorobenzene as internal standard.

^dEnantiomeric excess, determined by HPLC with a chiral stationary phase.

^eFrom ref (11).

^fFrom ref (21).

^gIsolated yield.