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. Author manuscript; available in PMC: 2012 Jun 17.
Published in final edited form as: Tetrahedron. 2011 Jun 17;67(24):4442–4448. doi: 10.1016/j.tet.2011.02.066

Table 2.

Scope of the photocatalytic [4+2] cycloaddition.a

Entry Methodb Substrate Product Time Yieldc
graphic file with name nihms280574t2.jpg graphic file with name nihms280574t3.jpg
1 A Ar = Ph 1 h 86%
2 A Ar = 4-Cl-C6H4 30 min 70%
3 A Ar = 4-CF3-C6H4 30 min 83%d
4 A Ar = 4-AcO-C6H4 1 h 76%
5 A Ar = 2-naphthyl 1.5 h 77%
6 A Ar = 2-furyl 30 min 77%
7 A Ar = 2-F-C6H4 30 min 84%
8 A Ar = 2-Me-C6H4 6 h 5% e
graphic file with name nihms280574t4.jpg graphic file with name nihms280574t5.jpg
9 A R = CH2OBn 20 min 76%
10 A R = Me 2 h 39%
11 B R = Me 10 min 73%
12 B R = i-Pr 1.5 h 58%
13 B R = t-Bu 6 h 12%e
14 B graphic file with name nihms280574t6.jpg graphic file with name nihms280574t7.jpg 5 h 17% e
a

All reactions were irradiated with a 200 W tungsten filament light bulb at a distance of 30 cm.

b

Method A: Bis(enone) substrate (1 equiv), Ru(bpy)3Cl2(0.05 equiv), LiBF4 (2 equiv), i-Pr2NEt (3 equiv), and H2O (10 equiv) in degassed MeCN (0.1 M). Method B: Bis(enone) substrate (1 equiv), Ru(bpy)3Cl2 (0.05 equiv), Mg(ClO4)2 (2 equiv), and i-Pr2NEt (5 equiv) in degassed MeCN (0.025 M).

c

Data represent the average isolated yields from two reproducible experiments, unless otherwise noted.

d

Isolated yield of a single experiment.

e

Yield of a single experiment, determined by 1H NMR spectroscopy against an internal standard.