Reactions of endocyclic linearly conjugated dienolates with Michael acceptors leading to bicyclo[2.2.2]octane derivatives. Application to the synthesis of C13 degradation products of carotenoids
作者:Nobuhiko Ito、Takeaki Etoh
DOI:10.1039/p19960002397
日期:——
The endocyclic linearly conjugated dienolates from substituted cyclohex-2-enones react with but-3-en-2-one, substituted methyl propenoates, but-3-yn-2-one and methyl propiolate to afford bicyclo[2.2.2]-oct-2-en-1-ols 10a–c, 14a–c and bicyclo[2.2.2]octa-2,5-dien-1-ols 15a,b. The AlCl3-catalysed reaction of 3,5,5-trimethyl-1-(trimethylsiloxy)cyclohexa-1,3-diene 3 with (E)-4-acetoxy- and (E)-4-methoxy-but-3-en-2-one provides trans-8-acetoxy-7-acetyl-3,5,5-trimethyl-1-(trimethylsiloxy)bicyclo[2.2.2]oct-2-enes 22, 23 and trans-7-acetyl-8-methoxy-3,5,5-trimethyl-1-(trimethylsiloxy)bicyclo[2.2.2]oct-2-enes 24, 25. Starting from these bicyclo[2.2.2]octenes, the C13 degradation products of carotenoids including 3-oxo-α-ionone 20, blumenol-C 27 and 1,3,7,7-tetramethyl-2-oxabicyclo[4.4.0]decan-9-one 29 have been synthesized.
从取代环己烯-2-酮衍生的内周期性线性共轭烯醇盐与丁-3-烯-2-酮、取代甲基丙烯酸酯、丁-3-炔-2-酮和美克丙酸乙酯反应,生成双环[2.2.2]八-2-烯-1-醇10a–c、14a–c和双环[2.2.2]八-2,5-二烯-1-醇15a,b。3,5,5-三甲基-1-(三甲基硅氧基)环己烯-1,3-二烯3与(E)-4-乙氧基和(E)-4-甲氧基-丁-3-烯-2-酮的铝氯化物催化反应生成反式-8-乙氧基-7-乙酰基-3,5,5-三甲基-1-(三甲基硅氧基)双环[2.2.2]八-2-烯22, 23和反式-7-乙酰基-8-甲氧基-3,5,5-三甲基-1-(三甲基硅氧基)双环[2.2.2]八-2-烯24, 25。以这些双环[2.2.2]八烯为起始材料,合成了包括3-氧代-α-紫罗兰酮20、布鲁梅诺-C 27和1,3,7,7-四甲基-2-氧双环[4.4.0]癸-9-酮29在内的类胡萝卜素C13降解产物。