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Download fileNoble-Metal-Free Deoxygenation of Epoxides: Titanium Dioxide as a Photocatalytically Regenerable Electron-Transfer Catalyst
journal contribution
posted on 2014-06-06, 00:00 authored by Yasuhiro Shiraishi, Hiroaki Hirakawa, Yoshiki Togawa, Takayuki HiraiCatalytic deoxygenation of epoxides
into the corresponding alkenes
is a very important reaction in organic synthesis. Early reported
systems, however, require noble metals, high reaction temperatures
(>373 K), or toxic reducing agents. Here, we report a noble-metal-free
heterogeneous catalytic system driven with alcohol as a reducing agent
at room temperature. Photoirradiation (λ <420 nm) of semiconductor
titanium dioxide (TiO2) with alcohol promotes efficient
and selective deoxygenation of epoxides into alkenes. This noble-metal-free
catalytic deoxygenation is facilitated by the combination of electron
transfer from surface Ti3+ atoms on TiO2 to
epoxides, which promotes deoxygenation of epoxides, and photocatalytic
action of TiO2, which regenerates oxidized surface Ti atoms
with alcohol as a reducing agent.