| 摘 要： | Both β-and γ-hydroxyketone structures are important units in biologically active molecules, synthetic drugs and fine chemicals.Although there are some routes available for their manufacture from pre-functionalized groups on one or two matrix molecule(s),the approaches to simply and simultaneously deposit two oxygen atoms from dioxygen into two specific C(sp~3) positions of pure saturated hydrocarbons have rarely succeeded because they are involved in the targeted activation of three inert C–H σ bonds all at once. Here, we show that a TiO_2-CH_3CN photocatalytic suspension system enables the insertion of dioxygen into one C(sp~3)–C(sp~3) bond of strained cycloparaffin derivatives, by which difunctionalized hydroxyketone products are obtained in a one-pot reaction. With the cleavage event to release strain as the directional driving force, as-designed photocatalytic reaction systems show 21 examples of β-hydroxyketone products with 31%–76% isolated yields for three-membered ring derivatives and 5 examples of γ-hydroxyketone products with 30%–63% isolated yields for four-membered ring substrates.~(18)O isotopic labeling experiments using ~(18)O_2, Ti~(18)O_2 and intentionally added H_2~(18)O, respectively, indicated that both oxygen atoms of hydroxyketone products were exclusively from dioxygen, suggesting a previously unknown H+/TiO_2-e-catalyzed arrangement pathway of the hydroperoxide intermediate to convert dioxygen into hydroxyketone units.
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