Enamides 3a-c and 6 crystallize in α-packing modes with short intermolecular distances of 3.7–4.0 Å between alkene carbon atoms of adjacent molecules related by a center of symmetry. Irradiation at 350 nm of these crystalline tertiary phenylethenyl enamides affords head-to-tail dimers 8a-c and 9, respectively, in 87–92% yield, in marked contrast to the E to Z isomerization that is the exclusive reaction
酰胺3a-c和6以α堆积模式结晶,相邻分子的烯烃碳原子之间的分子间距离较短,分子间距离为3.7-4.0Å,且对称中心相关。这些结晶的叔苯基
乙烯基烯酰胺在350 nm处的照射分别提供了头尾二聚体8a-c和9,产率为87-92%,这与E到Z异构化形成鲜明对比,E到Z异构化是溶液辐照时的唯一反应。酰胺3a和6。