Highly Stereoselective Synthesis of Biologically Active Conjugated Polyene Compounds

1. 水稻抗稻瘟病自卫物质的合成。稻瘟病防治是日本的重要课题之一。1984年，我们合成了水稻抗稻瘟病的自卫物质二态胆酸甲酯(1)及其类似物。1985年，建立了coriolate叔丁基和叔丁基(9E,11E,15Z)- 13羟基-9,11,15-十八烷基三烯酸酯的合成方法。这些化合物对稻瘟病无生物活性。看来这些酯类必须转化为羧酸才能表现出生物活性。虽然合成白蚁追踪信息素(3Z,6Z,8E)-3,6,8-十二癸烯-1-01的尝试以失败告终，但我们发现了一种新的合成方法，即在苯回流温度下，用二氧化硒氧化2,4-烷二烯酸酯合成2,5-二取代呋喃和硒烯。这是非常有趣的，因为在如此温和的条件下由二烯合成呋喃从未有过报道。十八聚烯酸的合成。第(1)节制备的化合物对果蝇的杀虫效果较弱，但在实际应用中并不有效。

1. Synthesis of self defensive substances in rice plant against rice blast disease. Protection of rice blast disease is one of important projects in Japan. In 1984, we could synthesize the methyl ester of dimorphecolic acid (1), the self defensive substance in rice plant against rice blast disease, and its analogs. In 1985, the synthesis of tert-butyl coriolate and tert-butyl (9E,11E,15Z)-13hydroxy-9,11,15-octadecatrienoate was established. These compounds showed no biological activity against rice blast disease. It seems that the esters should be converted to carboxylic acid for the manifestation of biological activity.2. Although the attempts to synthesize termite trail-following pheromone, (3Z,6Z,8E)-3,6,8-dodecatrien-1-01 resulted in failure, we found a new and novel synthetic method of 2,5-disubstituted furans and selenophenes via oxidation of 2,4-alkadienoic ester with selenium dioxide at the reflux temperature of benzene. It is very interesting because synthesis of furans from dienes under such a mild condition has never been reported.3. Synthesis of octadecapolyenoic acid. Insecticidal test of compounds prepared in section (1) to drosophilae showed weak effectiveness, but it is not efficient practically.