A New Polyene Analog : Its Preparation and Photo-Reaction

我们使用我们原有的方法合成了新的七-2，4，6-三烯，该方法是基于β-烷氧基烯基锂的Wittig型烯化反应。下面显示了一个简单的过程。它包括两个步骤，第一步是β-烷氧基烯基锂与醛和酮的亲电加成，第二步是烯丙醇的水解。我们成功地完成了醛和酮的α-亚硫基、α-硒基和α-氰基甲酰化反应。串联甲酰化反应分别得到了光敏的2，4，6-三(苯亚硫基)-，4-氰基-2，6-二(苯亚硫基)-和6-cyano-2，4-bis(phenyl-sulfenyl)hepta-2，4，6-trienals，。这些三烯的光反应经过新的串联环化反应得到2-氧杂-或2-氮杂-双环[3.3.0]八-3，7-二烯。而β-全氟烷基-β-烷氧基烷基锂与醛反应生成了α，β不饱和的全氟烷基酮，这是制备含氟生物活性化合物的新型前体。然而，串联的全氟酰化反应得到了4，6-二(全氟烷基)-2H-吡喃，而不是2，4-二烯基酮。综上所述，我们合成的几种2，4，6-七三烯类化合物都具有很高的光敏性，可以得到新的双环化合物。特别是，2-氰基庚三烯的制备导致了草双环化合物的直接形成，而不是三烯的形成。

We have performed the syntheses of the new hepta-2,4,6-trienals using our original methodology, which was based on the Wittig type olefinations using β-alkoxyalkenyl lithiums. A simple process has been shown as follows. It contains two steps, a first is a electrophilic addition of the β-alkoxyalkenyl lithium with aldehydes and ketones, a second is a hydrolysis of the allylic alcohols. We have succeeded the α-sulfenyl-, α-selenenyl and α-cyano formylation of aldehydes and ketones. The tandem formylation gave the photo-sensitive 2,4,6-tris(phenylsulfenyl)-, 4-cyano-2,6-bis(phenylsulfenyl)- and 6-cyano-2,4-bis(phenyl-sulfenyl)hepta-2,4,6-trienals, respectively. Photo-reactions of these trienals underwent the new tandem cyclization to afford the 2-oxa- or 2-aza-bicyclo[3.3.0]octa-3,7-dienes. While, the β-perfluoroalkyl-β-alkoxyalkenyl lithiums with aldehydes and the successive hydrations afforded α,β-unsaturated perfluoroalkyl ketones, which were the novel precursors in the preparations of the fluorine-containing bioactive compounds. However, tandem perfluoroacylations gave the 4,6-bis(perfluoroalkyl)-2H-pyrans, not the 2,4-dienyl ketones. In summary, the several kinds of 2,4,6-heptatrienals we prepared here, are found to be highly-photo-sensitive to give the new bicyclic compounds. In particular, the preparation of the 2-cyanoheptatrienal lead to the direct formation of the oxabicyclic compounds, not the trienals.