Thermal Addition Reaction of Aroylketenes with Cyclic Enol Ethers.
作者:Toshiaki SAITHOH、Taichi OYAMA、Yoshie HORIGUCHI、Jun TODA、Takehiro SANO
DOI:10.1248/cpb.44.1298
日期:——
Thermal reaction of aroylketenes 2 with cyclic enol ethers such as 2, 3-dihydrofuran (A), 2, 3-dihydropyran (B), 1-trimethylsilyloxycyclopentene (C), 1-trimethylsilyloxycyclohexene (D), 3-trimethylsilyloxyindene (E), and 4-trimethylsilyloxy-1, 2-dihydronaphalene (F) was carried out to investigate the reactivity of 2 with these olefins. The main reaction was Michael-type addition to give the 1, 3-diketones 3 and 9, and the 1, 3, 5-triketones 13, 15, 18, and 20, depending on the olefins used. The addition of the olefins was facilitated by introduction of a nitro or chloro group into the aryl part of 2 and was profoundly retarded by steric hindrance of the olefins
芳酰基烯酮2与环状烯醇醚如2,3-二氢呋喃(A)、2,3-二氢吡喃(B)、1-三甲基硅氧基环戊烯(C)、1-三甲基硅氧基环己烯(D)、3-三甲基硅氧基茚(E)和4-三甲基硅氧基-1,2-二氢萘(F)的热反应被进行,以研究2与这些烯烃的反应性。主要反应是迈克尔型加成,产生1,3-二酮3和9以及1,3,5-三酮13、15、18和20,具体取决于所用的烯烃。烯烃的加入因2的芳基部分引入硝基或氯原子而得到促进,并因烯烃的空间位阻而显著减慢。