申请人:Kao Corporation
公开号:US05907048A1
公开(公告)日:1999-05-25
To provide a simple process for economically preparing a dihydropyrane compound at a high productivity and a high reaction yield. To use a compound selected from the group consisting of a base and a compound (VIII) having a weaker coordination power to the Lewis acid than the aldehyde compound and having an activity to dissolve the Lewis acid, coordinated by the compound (VIII), in a solvent as a co-catalyst in reacting aldehyde with a diene compound in the presence of a Lewis acid to prepare a 5,6-dihydro-2H-pyrane compound represented by formula (III): ##STR1## in which R.sup.1 represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, aryl group which may be substituted with alkyl group, having 6 to 12 total carbon atoms; R.sup.2 and R.sup.3 represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
提供一种简单的方法,以高产率和高反应收率经济地制备二氢吡喃化合物。在存在路易斯酸的情况下,使用从羧酸和化合物(VIII)中选择的一种化合物作为协同催化剂,其中化合物(VIII)具有较弱的路易斯酸配位能力,具有溶解路易斯酸的活性,并在溶剂中与路易斯酸配位,与醛和二烯化合物反应,制备由式(III)表示的5,6-二氢-2H-吡喃化合物:##STR1## 其中R.sup.1表示氢原子,具有1至12个碳原子的烷基,具有6至12个总碳原子的可以被烷基取代的芳基基团; R.sup.2和R.sup.3表示氢原子或具有1至6个碳原子的烷基基团。