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. Author manuscript; available in PMC: 2008 Sep 15.
Published in final edited form as: J Am Chem Soc. 2007 May 16;129(23):7216–7217. doi: 10.1021/ja069019d

Table 3.

Scope of Dual Catalyst Heteroatom Diels-Alder Reaction. a

Entry R mol% (S)-VAPOL Reaction Time (h) Series Yield b (%) ee c (%)
1 Ph 5 24 b 85 90
2 2-MeC6H4 5 24 c 83 93
3 1-Naphthyl 10 24 d 78 90
4 4-BrC6H4 5 24 e 84 89
5 4-NO2C6H4 10 24 f 69 73
6 4-MeOC6H4 10 48 g 71 90
7 4-F,2-MeC6H3 5 50 h 84 89
8 trans-β-styryl 5 24 i 11 0
9 1-Cyclohexenyl 10 46 j 45 93
10 t-Butyl 5 47 k 0 —
11 Cyclohexyl 10 24 l 90 93
12 i-Propyl 10 48 m 64 90
13 n-Heptyl 5 24 n 41 d 0
a

All reactions performed at 0.2 M in imine. The diene was added over 3 hours via syringe pump. Catalyst 8 was prepared from 100 mol% B(OPh)3 and the amount of (S)-VAPOL indicated in the Table.

b

Isolated yield after silica gel chromatography.

c

Determined by chiral HPLC analysis.

d

Background reaction with 100 mol% B(OPh)3 under the same conditions gives a 40% yield.