- 2-Aminopyrazine-functionalized MCM-41 nanoporous silica as a new efficient heterogeneous ligand for Cu-catalyzed allylic C–H bonds oxidation of olefins
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In spite of the importance of the application of allylic C–H bond oxidation of olefins in organic synthesis and existence of the numerous reports, lots of limitations such as large excess of the olefin respect to the oxidant, low chemical yield, long time of reaction and a large amount of the catalyst were reminded. We introduced a novel catalytic system using functionalized MCM-41 as catalyst support to promote efficiency of this reaction. The heterogeneous ligand Pyr-MCM-41 was prepared by substituted 2-aminopyrazine ligand on functionalized MCM-41 with 3-chloropropyltrimthoxysilane and characterized by FT-IR, XRD, SEM, EDX, BET, TGA, CHN techniques. In situ immobilized Pyr-MCM-41 by copper (I) trifluoromethanesulfonate (CuOTf) was applied in direct catalytic esterification of inert C–H bonds in olefins using various peresters at room temperature.
- Samadi, Saadi,Ashouri, Akram,Kamangar, Shadi,Pourakbari, Fatemeh
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- Effects of Silver Carbonate and p-Nitrobenzoic Acid for Accelerating Palladium-Catalyzed Allylic C-H Acyloxylation
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An allylic C-H acyloxylation of terminal alkenes with 4-nitrobenzoic acid was assisted by a bidentate-sulfoxide-ligated palladium catalyst combined with 1,4-benzoquinone and Ag2CO3 under mild reaction conditions. The catalytic activity was remarkably enhanced by Ag2CO3 as an additive and 4-nitrobenzoic acid as a carboxylate source; both components were essential to exhibiting high catalytic activity, high branch selectivity, and a wide substrate scope with low loading of the palladium catalyst. Branch-selective allylic acyloxylation of ethyl 7-octenoate (1a) gave the product which was led to ethyl 6,8-dihydroxyoctanoate (5), a useful synthetic intermediate of (R)-α-lipoic acid.
- Skhiri, Aymen,Nagae, Haruki,Tsurugi, Hayato,Seki, Masahiko,Mashima, Kazushi
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p. 7044 - 7048
(2021/09/13)
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