A New Method for Installation of Aryl and Alkenyl Groups onto a Cyclopentene Ring and Synthesis of Prostaglandins
作者:Yuichi Kobayashi、Modachur G. Murugesh、Miwa Nakano、Eisuke Takahisa、Shahid B. Usmani、Takayuki Ainai
DOI:10.1021/jo020375y
日期:2002.10.1
establishing the generality of the reaction (Table 2, eqs 6 and 7). Starting with the products of the coupling reaction, syntheses of the prostaglandin intermediates 13 and 14 (for 11-deoxy-PGE(2) and PGA(2)) and Delta(7)-PGA(1) methyl ester (15) were accomplished efficiently. During these investigations, LDA, LiCA, and LHMDS were found to be equally efficient bases for aldol reaction at the alpha' (alpha prime)
为了构建合成环戊烷的新策略,研究了过渡金属催化的顺式4-环戊烯-1,3-二醇单乙酸酯1与硬亲核试剂R(T)-m的偶联反应(图1中的等式1) 。尽管使用PhZnCl,PhSnMe(3),[Ph-B(Me)(OCH(Me)CH(Me)O)]-Li(+)(6a)(源自硼酸酯4a(R(T)= Ph)和MeLi)在钯或镍催化剂的存在下会导致产生未知化合物烯酮16和/或酮17或回收1,新的硼酸盐5a(由4a和n-BuLi衍生)在室温下在THF中存在镍催化剂(NiCl(2)(PPh(3))(2))提供了反式偶合产物2a(R(T)= Ph)和3a(R(T)= Ph)综合产量高,但产品比率低至0.9:1。比例提高到13:通过向反应混合物中加入t-BuCN和NaI,得到1。这是1与硬亲核试剂反应的第一个成功实例,用添加剂实现的比例增加是前所未有的。该试剂系统(硼酸盐5(1.2-1.8当量),NiCl(2)(P