Asymmetric bromohydroxylation of cinnamyl alcohols^a.

Entry	Substrate	Product	Yieldb (%)	eec (%)
1	X = p-Br, 1a	2a (X-ray)	70	83
2	X = p-Cl, 1b	2b	64	80
3	X = p-F, 1c	2c	75	76
4d	X = p-Ph, 1d	2d	87	90
5	X = p-Me,1e	2e (X-ray)	76	82
6	X = m-Me,1f	2f	71	62
7	X = o-Me,1g	2g	77	70
8	X = H,1h	2h	46	55
9	X = Br, 1i	2i	70	80
10	X = Cl, 1j	2j	71	80
11	X = F, 1k	2k	84	80
12	X = Me, 1l	2l	73	82
13	X = Br, 1m	2m	72	95
14	X = Cl, 1n	2n	78	94
15	X = F, 1o	2o	83	91
16	X = Ph, 1p	2p	84	94
17	X = Me, 1q	2q	87	90
18e			75	90
19			31	80

^aReactions were carried out with substrate 1 (0.50 mmol), (DHQD)₂PHAL (0.050 mmol), (−)-CSA (0.050 mmol), and PhCONHBr (0.60 mmol) in CH₃CN (5.0 mL) and water (0.50 mL) at −30 °C for 72 h unless otherwise noted.

^bIsolated yield.

^cDetermined by chiral HPLC analysis. For entry 1, the absolute configuration was determined by comparing the optical rotation of the corresponding epoxide with the reported one¹¹ upon treatment with K₂CO₃ in acetone (Scheme 3). For others, the absolute configurations were tentatively assigned by analogy.

^dThe reaction was carried out at −40 °C for 168 h.

^eMeOH was used as nucleophile.