<i>Lone</i>Selectivity of the Decatungstate-Sensitized Photooxidation of 1-Substituted Cycloalkenes
作者:Michael Orfanopoulos、Ioannis N. Lykakis
DOI:10.1055/s-2004-832803
日期:——
Decatungstate-sensitized oxidation of alkyl and phenyl substituted cycloalkenes in the presence of molecular oxygen shows a general preference for hydrogen abstraction on the congested side of the double bond.
Photoexcitation of contact charge-transfer (CCT) pairs of 1-arylcyclohexenes 1 (aryl: phenyl, 4-methylphenyl, and 4-methoxyphenyl) and oxygen in acetonitrile and benzene gave 1,2-epoxy-1-arylcyclohexanes 2 as major products together with 2-aryl-2-cyclohexen-1-ols and acetophenones 4. Similar irradiation of the CCT pairs in methanol/acetonitrile afforded mainly 2-aryl-2-methoxycyclohexanols instead of 2 and small amounts of 1-aryl-1-methoxycyclohexanes, 2-aryl-2-cyclohexen-1-ones, and 4. The formation of these products can be explained by photoinduced electron transfer in the excited CCT pairs generating radical cations of 1 and superoxide anions.