Table 1.

Enantioselective dioxytosylation of styrenes 1 using aryl-λ³-iodanes 4.^a

			Yield (%)b
Entry	Substrate	Reagent	3	5	ee of 3 (%)c,d
1	1a (X = H)	4a	53	15	70 (S)
2	1a (X = H)	4b	49	16	80 (S)
3	1a (X = H)	4c	41	14	78 (S)
4	1a (X = H)	4d	41	22	70 (S)
5	1a (X = H)	4e	80	20	92 (S)
6	1b (X = p-Cl)e	4a	63	6	70
7	1b (X = p-Cl)e	4b	46	5	76
8	1b (X = p-Cl)e	4e	79	5	90
9	1c (X = o-Me)	4a	7	34	79
10	1c (X = o-Me)	4e	10	35	96

^aThe reaction was carried out at −50 °C in dichloromethane containing 4 (47 mM), TsOH (86 mM), and 1 (43 mM) for 4 h. ^bThe yield was determined by ¹H NMR using an internal standard. ^cThe ee was determined by chiral HPLC using a Daicel CHIRALPAK AD column (ø 4.6 mm × 250 mm). ^dPreferential configuration of product 3. The absolute stereochemistry of 3b and 3c was not determined. ^eThe reaction was carried out for 20 h.