摘要
6-取代-1,4-环辛二烯与单重态氧立体有选择地氧化成顺式5,8-和反式5,6-二取代-1,3-环辛二烯的含氧衍生物。依据产物的分子结构推知,6-取代-1,4-环辛二烯发生“ene”反应时的优势构象不同于环辛烷,而是具有角张力的扭曲构象(Ⅰ),这为研究环烯的分子构象提供了一种实验方法。用Monroe法测定了6-取代-1,4-环辛二烯对单重态氧反应的β值。其反应活性顺序为:3>1>4>1,5-环辛二烯>2>5。表明推电子取代基增加了同单重态氧反应的能力,而吸电子取代基则降低了同单重态氧的反应能力。但是不论取代基性质如何,都不能改变“ene”反应的本质。
The singlet oxygenation of 6-substituted-1, 4-cyclooctadienes gave cis-5, 8 and
trans-5, 6-difunctionalized-1, 3-cyclooctadienes stereoselectively. In according to the
molecular structures of the products, the conformation of 6-substituted-1, 4-cycloocta-
dienes being of twisted conformer (Ⅰ) was infered when 'ene' reaction occured. It is
informative for investigating molecular conformation of medium size cycloalkenes.
The order of reactivity toward singlet oxygen decreases as following: 3>1>4>1, 5-
cyclooctadiene>2>5. It appears that electron-donating substituents enhance the ability
of 'ene' reaction, while electron-withdrawing substituents reduce this ability, but they
can not alter the nature of sensitized photooxygenation of 6-substituted-1, 4-cycloocta-
dienes, i. e. the preference of the 'ene' reaction over the 1, 5-cycloaddition.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1989年第2期147-151,共5页
Acta Chimica Sinica
基金
国家自然科学基金
