All-at-once arrangement of both oxygen atoms of dioxygen into aliphatic C(sp^(3))–C(sp^(3))bonds for hydroxyketone difunctionalization  

作　　者：Xiaofeng Qiao Yuhan Lin Jiazhen Li Wanhong Ma Jincai Zhao 

机构地区：[1]Key Laboratory of Photochemistry,CAS Research/Education Center for Excellence in Molecular Sciences,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China Chemistry》2021年第5期770-777,共8页中国科学（化学英文版）

基　　金：This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB36000000);the National Natural Science Foundation of China(21590811,21777167,21827809);and the National Key R&D Program of China(2018YFA0209302).

摘　　要：Bothβ-andγ-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–Hσbonds all at once.Here,we show that a TiO_(2)-CH_(3)CN 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 ofβ-hydroxyketone products with 31%–76%isolated yields for three-membered ring derivatives and 5 examples ofγ-hydroxyketone products with 30%–63%isolated yields for four-membered ring substrates.^(18)O isotopic labeling experiments using^(18)O2,Ti^(18)O_(2) and intentionally added H218O,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.

关 键 词：TiO2 photocatalysis β-orγ-hydroxyketones strained cycloalkanes dioxygen activation 

分 类 号：O623.52[理学—有机化学]