. Author manuscript; available in PMC: 2017 Jul 21.

Published in final edited form as: J Org Chem. 2008 Sep 17;73(20):7963–7970. doi: 10.1021/jo800951q

Table 1.

Attempted cyclizations of epoxide 19.

Trial #	Acid	Time (min.)	T (°C)	Distribution (by gc vs int std)
Trial #	Acid	Time (min.)	T (°C)	19	20	21
1	Ti(OiPr)₄	5	−78	100	0	0
2	Ti(OiPr)₄	5	rt	100	0	0
3	Ti(OiPr)₄	1.5	rt	100	0	0
4	TiCl₄	5	−78	0	0	0
5	SnCl₄	5	−78	0	0	0
6	CH₃AlCl₂	30	−78	0	17^a	8^a
7	In(OTf)₃	1	rt	0	65	0
8	In(OTf)₃	5	−78	55	29	0
9	In(OTf)₃	5	0	0	60	2
10	In(OTf)₃	8	−35	14	36	3
11	BF₃·Et₂O	0.5	−78	0	44	6
12	BF₃·Et₂O	1	−78	0	64	11
13	BF₃·Et₂O	2	−78	0	68^a	7^a
14	BF₃·Et₂O	4	−78	0	49^a	11^a
15	BF₃·Et₂O	8	−78	0	51	15

Isolated yields following column chromatography.