Photoinduced 6π-Electrocyclization of a 1,3,5-Hexatriene System Containing an Allomaltol Fragment.

For the first time, the possibility of photocyclization of the 1,3,5-hexatriene system containing a fragment of allomaltol was demonstrated. A preparative method for the synthesis of previously unknown benzo[5,6]chromeno[8,7-d]oxazole-2,7(3H)-diones was developed based on the investigated photoreaction. A distinctive feature of this approach is the modification of the starting terarylenes aimed at blocking the competitive process leading to side reactions of the pyranone fragment. It was shown that the proposed photocyclization of substituted oxazol-2-ones can be used for the photogeneration of biologically active alcohols and various acids. The structure of one of the cyclization products was determined by X-ray diffraction.