Mild Stereoselective Synthesis of Fully Protected 1,6-Dioxaspiro[4.5]dec-3-ene Derivatives of Sugars
作者:Romualdo Caputo、Annalisa Guaragna、Giovanni Palumbo、Silvana Pedatella、Francesco Solla
DOI:10.1002/1099-0690(20022)2002:3<534::aid-ejoc534>3.0.co;2-r
日期:2002.2
5]dec-3-ene derivatives of sugars are prepared in three steps, starting from fully protected glycono-1,5-lactones. The procedure exploits a reagent previously devised in our laboratory, the 3-C-lithiated 5,6-dihydro-1,4-dithiin-2-yl[(4-methoxybenzyl)oxy]methane (2), that acts as an allylic alcohol anion equivalent leading to three carbon elongations by introduction of a fully protected hydroxypropenyl
从完全保护的1,5-内酯内酯开始,糖的全苄基化1,6-二氧杂螺并[4.5] dec-3-ene衍生物是分三步制备的。该方法利用了以前在我们实验室中设计的一种试剂,它是烯丙基的3- C-锂化5,6-二氢-1,4-二硫-2--2-基[(4-甲氧基苄基)氧基]甲烷(2)。醇阴离子当量通过引入完全保护的羟基丙烯基部分导致三个碳延伸。2对起始糖基内酯的攻击是选择性地从β面发生的,导致生成半缩醛衍生物,然后通过与BF 3 ·Et 2反应完成其螺环化反应。O.可以对完全保护的不饱和螺缩醛进行选择性脱硫,以进一步加工游离双键。