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. Author manuscript; available in PMC: 2008 Aug 13.
Published in final edited form as: J Am Chem Soc. 2005 Dec 7;127(48):16778–16779. doi: 10.1021/ja054085l

Table 1.

Survey of Solvents for the Tandem Cyclizationa

graphic file with name nihms60234f2.jpg
entry Solvent T(°C) time (h) % 4+5 Ratio (4 : 5)
1b MeOH 25 24 83c 94 : 6
2 MeOH 60 10 82c 93 : 7
3 t-AmylOH 60 48 10d 90 : 10
4 i-PrOH 60 3 80 71 : 29
5b CF3CH2OH 60 24 80 >99 : 1
6e CF3CH2OH 60 22 76 >99 : 1
a

Conditions: 0.25 equiv PBu3, 0.05 M 2.

b

1 equiv PBu3 was used.

c

Contaminated with 20% MeOH-adducts of 4 and 5.

d

Aldol product (19%) and 3 (42%) were also isolated.

e

1 equiv PMe3 was used.