configuration at C(2) of the bicyclic 1,3-oxazines formed by the cyclization of alicyclic 1,3-aminoalcohols with aldehydes is determined by the dominant conformation of the product. The first X-ray diffraction evidence is given for the N-outside conformation of compounds of this type.
快速,自发的差向异构发生在一个新的非对映异构体(r -4,c-2,c-5)-2-(对
硝基苯基)-3-甲基-4,5-四亚甲基四氢-的C(2)手性中心1,3-恶嗪导致的结论是,通过脂环族1,3-
氨基醇与醛的环化作用形成的双环1,3-恶嗪在C(2)的构型是由产物的主要构象决定的。给出了这种化合物的N-外部构象的第一个X射线衍射证据。