Room-Temperature Metallation of 2-Substituted 1,3-Dithiane Derivatives and Subsequent Coupling with 2,3-Disubstituted Oxiranes
作者:Mitsuaki Ide、Masaya Nakata
DOI:10.1246/bcsj.72.2491
日期:1999.11
2-Substituted 1,3-dithiane derivatives, (S)-1-(t-butyldiphenylsiloxy)-2-(1,3-dithian-2-yl)propane (9), (S)-1-(t-butyldimethylsiloxy)-2-(1,3-dithian-2-yl)propane, 1-(t-butyldiphenylsiloxy)-2-(1,3-dithian-2-yl)-2-methylpropane, and 1,2-bis(t-butyldiphenylsiloxy)-3-(1,3-dithian-2-yl)propane, were subjected to lithiation in THF with n-BuLi at room temperature (r.t.); the resulting anions reacted with 2,3-disubstituted oxirane, trans-2-methyl-3-(triphenylmethoxymethyl)oxirane (22), at r.t., giving the coupling products in satisfactory yield. On the other hand, the lithium salt formed in ether from (S)-2-(1,3-dithian-2-yl)-1-(4-methoxybenzyloxy)propane with n-BuLi at r.t. reacted with 22 at r.t. in the presence of hexamethylphosphoric triamide to afford the coupling product in moderate yield. In addition, a mixed organometallic reagent, n-BuLi / Bu2Mg, was found to be an effective metallation reagent for 9 and the resulting anion reacted with 22 to afford the coupling product in good yield.
2-取代的
1,3-二噻烷衍
生物、(S)-1-(叔丁基二苯基
硅氧基)-2-(
1,3-二噻烷-2-基)
丙烷 (9)、(S)-1-(叔丁基二甲基
硅氧基)-2-(
1,3-二噻烷-2-基)
丙烷、1-(叔丁基二苯基
硅氧基)-2-(1、和 1,2-双(叔丁基二苯基
硅氧基)-3-(
1,3-二噻烷-2-基)
丙烷。t.)下与
正丁基锂在
四氢呋喃中发生
锂化反应;生成的阴离子与 2,3-二取代
环氧乙烷、反式-2-甲基-3-(三苯甲氧基甲基)
环氧乙烷(22)在 r.t、得到令人满意的偶联产物。另一方面,(S)-2-(
1,3-二噻烷-2-基)-1-(4-甲氧基苄氧基)
丙烷与正
叔丁基锂在
乙醚中形成的
锂盐在六甲基
磷酸三酰胺存在下与 22 在r.t.发生反应,得到偶联产物,产率中等。此外,还发现一种混合有机
金属试剂 n-BuLi / Bu2Mg 是 9 的有效
金属化试剂,由此产生的阴离子与 22 反应得到偶联产物,收率很高。