An Efficient and HighlyStereoselective Synthesis of<i>gala</i>-Quercitolfrom 1,4-Cyclohexadiene
作者:Hasan Seçen、Metin Balci、Arif Baran
DOI:10.1055/s-2003-40517
日期:——
gala-Quercitol was synthesized from 1,4-cyclohexadiene in seven steps and overall yield of 68%. Reaction of 5,6-dibromo-2,2-dimethylhexahydro-1,3-benzodioxole, synthesized from 1,4-cyclohexadiene in three steps, with excess NaOMe gave (3aα,5α,7aα)-5-methoxy-2,2-dimethyl-3a,4,5,7a-tetrahydro-1,3-benzodioxole. cis-Hydroxylation of the benzodioxole followed by acetylation with AcCl gave 5-O-methyl-gala-quercitol tetraacetate from which gala-quercitol was obtained by hydrolysis and demethylation with aq HBr (47%).
以1,4-环己二烯为原料,经过七步合成半乳糖醇,总收率为68%。 5,6-二溴-2,2-二甲基六氢-1,3-苯并二氧杂环戊烯,由 1,4-环己二烯分三步合成,与过量的 NaOMe 反应得到 (3aα,5α,7aα)-5-甲氧基- 2,2-二甲基-3a,4,5,7a-四氢-1,3-苯并间二氧杂环戊烯。苯并间二氧杂环戊烯的顺式羟基化,然后用AcCl乙酰化,得到5-O-甲基-半乳糖-槲皮醇四乙酸酯,通过水解和用HBr水溶液(47%)去甲基化从中获得半乳糖-槲皮醇。