Heterocyclic derivative syntheses by palladium-catalyzed oxidative cyclization -: Alkoxycarbonylation of substituted γ-oxoalkynes
Heterocyclic derivative syntheses by palladium-catalyzed oxidative cyclization -: Alkoxycarbonylation of substituted γ-oxoalkynes
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DOI：
10.1021/jo050155v
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发表时间：
2005-06-24
影响因子：
3.6
通讯作者：
Cassoni, S
中科院分区：
文献类型：
--
作者：
Bacchi, A;Costa, M;Cassoni, S
含有不同取代基的4-Yn-1-酮、丙-2-炔基α-酮酯和丙-2-炔基α-酮酰胺在氧化羰基化条件下发生催化反应，以令人满意的收率得到四氢呋喃、二氧戊环和恶唑啉、二氢吡啶酮和四氢吡啶二酮衍生物。反应在 MeOH 或 MeCN/MeOH 混合物中于 65100 摄氏度、催化量的 PdI2 与 KI 存在下、在 32 bar（25 T）的 CO 和空气的 3:1 混合物中进行。反式和顺式 5-exo-dig 环化模式导致不同产物的形成。人们发现，在较高温度和较长时间反应时形成的环戊烯酮、二氢吡啶酮和四氢吡啶二酮衍生物也可以通过涉及不寻常重排的四氢呋喃和恶唑啉衍生物的酸处理来选择性地获得。通过X射线衍射分析证实了6-甲氧基-2,2二甲基-3-氧代-5-苯基-2,3-二氢吡啶-4-甲酸甲酯和2,2,5-三甲基3,6-二氧代-1,2,3,6-四氢吡啶-4-甲酸甲酯的结构。
4-Yn-1-ones containing different substituents, prop-2-ynyl alpha-ketoesters, and prop-2-ynyl alpha-ketoamides have been caused to react catalytically under oxidative carbonylation conditions to give tetrahydrofuran, dioxolane and oxazoline, dihydropyridinone, and tetrahydropyridinedione derivatives in satisfactory yields. Reactions were carried out in MeOH or MeCN/MeOH mixtures at 65100 degrees C in the presence of catalytic amounts of PdI2 in conjunction with KI under 32 bar (at 25 T) of a 3:1 mixture of CO and air. Anti and syn 5-exo-dig cyclization modes account for the formation of different products. It has been found that cyclopentenone, dihydropyridinone, and tetrahydropyridinedione derivatives, formed when the reaction is carried out at higher temperature and for a longer time, can also be selectively obtained through an acid treatment of tetrahydrofuran and oxazoline derivatives involving an unusual rearrangement. The structures of 6-methoxy-2,2dimethyl-3-oxo-5-phenyl-2,3-dihydropyridine-4-carboxylic acid methyl ester and 2,2,5-trimethyl3,6-dioxo-1,2,3,6-tetrahydropyridine-4-carboxylic acid methyl ester have been confirmed by X-ray diffraction analysis.