Co2(CO)8-mediated Endo Mode Cyclization of Epoxy-alcohol: Synthesis of 2-Ethynyl-3-hydroxy-2-methyltetrahydropyran and 2-Ethynyl-3-hydroxy-3-methyltetrahydropyran Derivatives.
作者:Chisato MUKAI、Sumie YAMAGUCHI、In Jong KIM、Miyoji HANAOKA
DOI:10.1248/cpb.49.613
日期:——
Successive treatment of 4, 5-epoxy-5-methyl-7-trimethylsilyl-6-heptyne-1-ol with Co2(CO)8 at 0 °C and a catalytic amount of BF3·OEt2 at −78 °C gave the tetrahydropyran derivatives with the cobalt-complexed moiety. Similarly 4, 5-epoxy-4-methyl-7-trimethylsilyl-6-heptyne-1-ol underwent ring closure under the above conditions to provide the corresponding tetrahydropyran derivatives. The preferential endo mode cyclization over the exo one was observed in these experiments.
连续对4, 5-环氧-5-甲基-7-三甲基硅基-6-庚炔-1-醇在0 °C下与Co2(CO)8进行处理,并在−78 °C下加入催化量的BF3·OEt2,得到含有钴复合体的四氢吡喃衍生物。同样,4, 5-环氧-4-甲基-7-三甲基硅基-6-庚炔-1-醇在上述条件下发生环闭合,生成相应的四氢吡喃衍生物。在这些实验中观察到优先发生内环化而非外环化现象。