A Pt-loaded TiO₂ photocatalyst successfully catalyzed the direct cross-coupling between various alkenes and tetrahydrofuran (THF) without any additional oxidizing agent. The reaction between cyclohexene and THF gave three cross-coupling products, namely, 2-cyclohexyltetrahydrofuran (A), 2-(cyclohex-2-en-1-yl)tetrahydrofuran (B) and 2-(cyclohex-1-en-1-yl)tetrahydrofuran (C), along with gaseous hydrogen. The mechanistic study revealed that these products were formed through different individual mechanisms: successive addition of two radical species, a 2-tetrahydrofuranyl radical and a hydrogen radical, to the double bond of cyclohexene for A, coupling of a 3-cyclohexenyl radical and a 2-tetrahydrofuranyl radical for B, and 2-tetrahydrofuranyl radical addition and hydrogen radical elimination at the double bond of cyclohexene for C. Among these three mechanisms, those for B and C are dehydrogenative. In this photocatalytic reaction system, since the cyclohexene molecule has enough reactivity, due to the localized π electron density, the Pt nanoparticles loaded on the TiO₂ function not as a metal catalyst but as an electron receiver to enhance the charge separation, although the dehydrogenative cross-coupling of benzene with THF requires Pd metal catalysis.

中文翻译：

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烯烃和四氢呋喃与负载铂的二氧化钛光催化剂之间的直接交叉偶联†

负载Pt的TiO ₂光催化剂成功催化了各种烯烃与四氢呋喃（THF）之间的直接交叉偶联，而无需任何其他氧化剂。环己烯和THF之间的反应给出了三个交叉耦合的产品，即，2- cyclohexyltetrahydrofuran（甲），2-（环己-2-烯-1-基）四氢呋喃（乙）和2-（环己-1-烯-1- -基）四氢呋喃（C）以及气态氢。的机理研究表明，这些产品是通过不同的机制个体形成：连续添加两种自由基种，2-四氢呋喃基基团和氢基团，环己烯的为双键甲，B的3-环己烯基和2-四氢呋喃基的偶合，以及C的环己烯双键的2-四氢呋喃基的加成和氢基的消除。在这三种机理中，B和C的机理是脱氢的。在这种光催化反应系统中，由于环己烯分子具有足够的反应性，由于局部π电子密度，负载在TiO ₂上的Pt纳米颗粒不仅起到金属催化剂的作用，而且还起到电子受体的作用，以增强电荷分离，尽管脱氢性苯与THF的交叉偶联需要Pd金属催化。