Titania-promoted carboxylic acid alkylations of alkenes and cascade addition-cyclizations.
Titania-promoted carboxylic acid alkylations of alkenes and cascade addition-cyclizations.
复制标题
二氧化钛促进烯烃的羧酸烷基化和级联加成环化。
DOI：
10.1021/jo4027929
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发表时间：
2014-02-07
期刊：
影响因子：
--
通讯作者：
O'Rourke C
中科院分区：
文献类型：
--
作者：
Manley DW;McBurney RT;Miller P;Walton JC;Mills A;O'Rourke C
光化学反应，采用二氧化钛和羧酸在干燥的厌氧条件下导致几种类型的C-C键形成过程与缺电子烯烃。烷基化的效率随羧酸中的取代基而明显变化。芳氧基乙酸与马来酰亚胺的反应导致级联过程，其中吡咯并色烯衍生物伴随烷基化琥珀酰亚胺。通过在不同条件下使用光氧化还原催化剂，可以在一定程度上调节这些产物中的一种或另一种的选择性。芳氧基乙酸通过包含2-烯基、2-芳基或2-肟基官能团而适于分子内环闭合，反应相当差。这些系统的反应物消耗和产物形成的配置文件，获得了原位NMR监测技术。测试了一系列不同催化剂形式的效率和易用性。所提出的机制，涉及空穴捕获在TiO 2表面的羧酸盐，然后由CO2损失，支持EPR光谱证据的中间体。氘标记表明，二氧化钛可能从表面羟基提供质子，并提供电子和空穴，因此既作为催化剂又作为反应伙伴。
Photochemical reactions employing TiO2 and carboxylic acids under dry anaerobic conditions led to several types of C–C bond-forming processes with electron-deficient alkenes. The efficiency of alkylation varied appreciably with substituents in the carboxylic acids. The reactions of aryloxyacetic acids with maleimides resulted in a cascade process in which a pyrrolochromene derivative accompanied the alkylated succinimide. The selectivity for one or other of these products could be tuned to some extent by employing the photoredox catalyst under different conditions. Aryloxyacetic acids adapted for intramolecular ring closures by inclusion of 2-alkenyl, 2-aryl, or 2-oximinyl functionality reacted rather poorly. Profiles of reactant consumption and product formation for these systems were obtained by an in situ NMR monitoring technique. An array of different catalyst forms were tested for efficiency and ease of use. The proposed mechanism, involving hole capture at the TiO2 surface by the carboxylates followed by CO2 loss, was supported by EPR spectroscopic evidence of the intermediates. Deuterium labeling indicated that the titania likely donates protons from surface hydroxyl groups as well as supplying electrons and holes, thus acting as both a catalyst and a reaction partner.
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影响因子：
2.1
作者：
Ballini, R;Bosica, G;Petrini, M
通讯作者：
Petrini, M
影响因子：
4.3
作者：
KUNNETH, R;FELDMER, C;KISCH, H
通讯作者：
KISCH, H
影响因子：
3.6
作者：
BAKER, FW;STOCK, LM;HOLTZ, HD
通讯作者：
HOLTZ, HD
影响因子：
4.3
作者：
Keck, H;Schindler, W;Kisch, H
通讯作者：
Kisch, H
TiO2 上甲基橙光降解过程中涉及活性物质的证据
影响因子：
3.7
作者：
Li, Wenjuan;Li, Danzhen;Shao, Yu
通讯作者：
Shao, Yu