Sc(OTf)3/TsOH: a highly efficient catalytic system for the synthesis of 2,6-dioxabicyclo[3,2,1]octane derivatives
作者:B.V. Subba Reddy、G. Narasimhulu、Y. Vikram Reddy、P.P. Chakravarthy、J.S. Yadav、B. Sridhar
DOI:10.1016/j.tetlet.2012.04.029
日期:2012.6
A variety of aldehydes undergo a tandem acetalization and intramolecular Prins cyclization with pent-4-ene-1,2-diol in the presence of 5 mol % scandium triflate and 15 mol % p-toluenesulfonic acid (TsOH) in dichloroethane at 80 °C to produce the corresponding bicyclic ethers, that is, 2,6-dioxabicyclo[3,2,1]octane derivatives in good yields and with high selectivity. The salient features of this methodology
在80°C的二氯乙烷中存在5 mol%三氟甲磺酸scan和15 mol%对甲苯磺酸(TsOH)的情况下,各种醛与戊-4-烯-1,2-二醇进行串联缩醛化和分子内Prins环化以高收率和高选择性生产相应的双环醚,即2,6-二氧杂双环[3,2,1]辛烷衍生物。该方法的突出特点是产率高,催化剂用量低和反应时间短。发现Sc(OTf)3和TsOH(1:3)的组合比单独使用Sc(OTf)3或TsOH更有效。