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. Author manuscript; available in PMC: 2010 Mar 16.
Published in final edited form as: Tetrahedron Asymmetry. 2009 Jan 30;20(1):1–63. doi: 10.1016/j.tetasy.2009.01.002

Table 11.

Enantioselective Diels-Alder cycloaddition of 424 with cyclopentadiene.

graphic file with name nihms166053t26.jpg
Conditions t (h) exo: endo endo ratio exo ratio
366a-Mg(ClO4)2 48 75 : 25 43 : 57 50 : 50
366a-Ce(OTf)4.H2Oa 75 70 : 30 50 : 50 50 : 50
425-Mg(ClO4)2 100 70 : 30 50 : 50 50 : 50
425-Ce(OTf)4.H2Oa 150 75 : 25 50 : 50 50 : 50
426-Mg(ClO4)2 24 80 : 20 47 : 53 43 : 57
427-Mg(ClO4)2 24 75 : 25 56 : 44 66 : 34
427-Ce(OTf)4.H2Oa 200 75 : 25 50 : 50 50 : 50
a

In the presence of molecular sieves.