Extension of the BAM-catalyzed iodolactonization to ε-membered lactones^a.

Entry	5/8	R	eeb (%)	Yieldc (%, isolated)
1	a	C6H5	88	71
2	b	2Np	87	64
3	c	p MeC6H4	77	87
4d	d	m MeC6H4	84	76
5	e	o MeC6H4	—	Trace
6	f	p FC6H4	93	65
7	g	m FC6H4	93	53
8e	h	m ClC6H4	96	21
9	i	p ClC6H4	91	70
10	j	p CF3C6H4	81	48
11f	k	3,5(CF3)2C6H3	10	10
12	l	m CHOC6H4	94	54
13	m	p PhC6H4	84	72
14	n	m MeOC6H4	90	63
15	o	p MeOC6H4	49	53
16	p	p (tBu)C6H4	83	66
17	q	5-(2-Methoxypyridine)	75	73
18	r	Me	63	42
19	s	Et	72	58
20	t	H	44	24g
	Substrate	Product
21		10	87	70
22		12	65	90
23d			92	19
24h	h	m ClC6H4	96	26
25h	n	m MeOC6H4	87	61

^aGeneral experimental details: the oxidant (100 mol%), iodine (100 mol%), and carboxylic acid were combined in solvent and stirred for 48 hours prior to workup and analysis; see ESI for complete details.

^bMeasured by HPLC using a chiral stationary phase.

^cIsolated yield after chromatography. Although column chromatography was successfully used at room temperature, many of the lactone products were noted to turn yellow, red, and then brown during final concentration in pure form. As a result, care should be taken to avoid heating during workup, and storage of pure materials at low temperature (<0 °C), or as a frozen solution in benzene, is highly recommended as standard practice. Yields measured from the crude reaction mixture (internal standard, ¹H NMR) were routinely higher.

^dReaction temperature = −20 °C.

^eReaction time = 4 days.

^fReaction temperature = 25 °C.

^gMeasured by ¹H NMR analysis of the crude reaction mixture due to product instability.

^hResults at 1 mmol scale for substrate.