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of
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Phenanthrene-9-
alkenes provide synthetically useful yields and selectivities. The
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topic of ongoing investigation.
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Bach has recently applied a similar concept to iminium ion
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13 The triplet energy of methyl crotonate has been estimated
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Ortuño, R. M.; Robb, M. A.; Branchadell, V. “Theoretical Study of
the Photochemical [2 + 2]-Cycloadditions of Cyclic and Acyclic
,-Unsaturated Carbonyl Compounds to Ethylene”, J. Org.
Chem. 2002, 67, 6070–6077.
14 Under current conditions, only styrenes with unsubstituted
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