Table 2.

Development of CPA-controlled endo-selective cyclization of mupirocin methyl ester (14).

Entry[a]	Catalyst	Solvent[b]	Conversion [%]	15/16[b]
1	(S)-17a	CH2Cl2	>98	66:34
2	(R)-17a	CH2Cl2	>98	74:26
3	(S)-17b	CH2Cl2	95	62:38
4	(S)-17c	CH2Cl2	>98	66:34
5	(R)-17c	CH2Cl2	>98	73:27
6	(S)-17d	CH2Cl2	>98	57:43
7	(R)-17d	CH2Cl2	>98	93:7
8	(S)-17e	CH2Cl2	>98	45:55
9	(R)-17e	CH2Cl2	>98	94:6
10	(R)-17f	CH2Cl2	>98	48:52
11[c]	(R)-17e	CH2Cl2	67	90:10
12[c]	(R)-17e	CyH	39	77:23
13[c]	(R)-17e	PhCF3	>98	92:8
14[c]	(R)-17e	PhMe	>98	95:5
15[c,d]	(R)-17e	PhMe	>98	97:3
16[c,e]	(R)-17e	PhMe	> 98	95:5
17[c,f]	(R)-17e	PhMe	>98	95:5
18[c, g]	(R)-17e	PhMe	93%	93:7

^[a]Conditions: 14 (0.02 mmol), solvent (0.2 m), 4 Å molecular sieves (MS), room temperature, 12 h.

^[b]Determined by RP HPLC.

^[c]Reactions were performed without 4 Å MS.

^[d]Reaction was performed with 100 mol% of the catalyst.

^[e]Reaction was performed with 10 mol% of the catalyst.

^[f]Reaction was performed with 5 mol% of the catalyst on a 0.20 mmol scale for 18 h.

^[g]Reaction was performed with 5 mol% of the catalyst in the presence of 5 mol% of water.