Macrocyclic Ring Closure of OH-assistedPrins Reaction. A new and efficient synthesis of (R,S)-muscone
作者:Karl H. Schulte-Elte、Arnold Hauser、G�nther Ohloff
DOI:10.1002/hlca.19790620817
日期:1979.12.12
macrocyclic ring closure has been developed. The monoacetal 4 of (Z,E)-4,8-dodecadienedial (3), easily obtainable from (Z,E,E)-1,5,9-cyclododecatriene (2), is treated with methallylmagnesium chloride, and the resulting C16-precursor 5 is subjected to acid-catalyzed cyclization in dilute (⩽1%) solutions. This results in formation of the bicyclic dihydropyran derivatives 6 which directly yield muscone (1) on heating
已开发出一种新的策略,用于使用大环封闭的OH辅助Prins反应合成Muscone (1)。易于从(Z,E,E)-1,5,9-环十二碳三烯(2)获得的(Z,E)-4,8-十二二烯醛(3)的单缩醛4用甲基烯丙基氯化镁处理,得到将C 16前体5在稀(约1%)溶液中进行酸催化的环化反应。这导致直接产生麝香酮(1)的双环二氢吡喃衍生物6的形成用饱和氢的贵金属催化剂加热。五步途径采用常规步骤中容易获得的原料,并具有极佳的总收率(约40%)。大环成环的这一新原理也已成功地用于制备3-甲基环翠烷酮(34),并且通常应适用于其他合适的环系统。