Heterocyclic Derivative Syntheses by Palladium-Catalyzed Oxidative Cyclization−Alkoxycarbonylation of Substituted γ-Oxoalkynes
作者:Alessia Bacchi、Mirco Costa、Nicola Della Cà、Bartolo Gabriele、Giuseppe Salerno、Silvia Cassoni
DOI:10.1021/jo050155v
日期:2005.6.1
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-2,2-dimethyl-3-oxo-5-phenyl-2,3-dihydropyridine-4-carboxylic acid methyl ester and 2,2,5-trimethyl-3,6-dioxo-1
已使包含不同取代基的4-Yn-1-one,丙-2-炔基α-酮酸酯和丙-2-炔基α-酮酰胺在氧化羰基化条件下催化反应,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,收率令人满意。反应在甲醇或MeCN / MeOH混合物中于65-100°C,在催化量的PdI 2和KI的存在下,在32 bar(25°C)的CO和空气的3:1混合物下进行。反和syn 5- exo-dig环化模式说明了不同产品的形成。已经发现,当在较高温度和更长的时间下进行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对四氢呋喃和恶唑啉衍生物进行酸处理而选择性地获得,所述酸处理涉及异常的重排。6-甲氧基-2,2-二甲基-3-氧代-5-苯基-2,3-二氢吡啶-4-羧酸甲酯和2,2,5-三甲基-3,6-二氧代-1的结构通过X射线衍射分析确认了2,3,6-四氢吡啶-4-羧酸甲酯。