Formation of Cyclic Ethers via the Palladium-Catalyzed Cycloaddition of Activated Olefins with Allylic Carbonates Having a Hydroxy Group at the Terminus of the Carbon Chain
作者:Masaru Sekido、Kouichi Aoyagi、Hiroyuki Nakamura、Chizuko Kabuto、Yoshinori Yamamoto
DOI:10.1021/jo0158332
日期:2001.10.1
The reaction of 1 with the hydroxy allylic carbonate 3 in the presence of catalytic amounts of Pd(2)dba(3).CHCl(3) and (o-tolyl)(3)P in THF at 50 degrees C afforded the corresponding cycloaddition products, tetrahydropyran derivatives 6, in good to high yields. The trans/cis ratios of the products were in the range of ca. 0-40/99-80. The reaction of 1a with the hydroxy allylic carbonate 4 needed higher
在催化量的Pd(2)dba(3).CHCl(3)和dppe在THF中的催化存在下,活化烯烃1与碳链末端具有羟基的烯丙基碳酸酯2的反应在室温下以高至非常高的产率得到相应的环加成产物四氢呋喃衍生物5。产物的非对映选择性(反式/顺式比)在约1。60-70 / 40-30。1与羟基烯丙基碳酸酯3在催化量的Pd(2)dba(3).CHCl(3)和(邻甲苯基)(3)P在THF中在50°C的反应下提供相应的环加成产物,四氢吡喃衍生物6,高至高收率。产物的反式/顺式比在约3的范围内。0-40 / 99-80。1a与羟基烯丙基碳酸酯4的反应需要更高的反应温度(大约100摄氏度),以31%的收率得到低价非对映异构体的环加成产物氧杂环丁烷7a。接下来,进行四氢呋喃和-吡喃衍生物的催化不对称合成。使用Trost配体15,尽管非对映选择性很低,但在环加成反应中却实现了从高到高的ee。使用Hayashi配体16,在环