A New Polyene Analog : Its Preparation and Photo-Reaction

我们已经进行了新的七-2，4，6-三烯醛的合成使用我们的原始方法，这是基于Wittig型烯化使用β-烷氧基烯基锂。一个简单的过程如下所示。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。我们成功地合成了醛、酮的α-硫烯基、α-硒烯基和α-氰基取代基。串联反应分别得到光敏的2，4，6-三苯硫基-2，4，6-庚三烯醛、4-氰基-2，6-双苯硫基-2，4-双苯硫基-6-氰基-2，4-庚三烯醛。这些三烯醛的光反应经历了新的串联环化反应，得到2-氧杂-或2-氮杂-双环[3.3.0]辛-3，7-二烯。而β-全氟烷基-β-烷氧基烯基锂与醛反应，再水合生成α，β-不饱和全氟烷基酮，是制备含氟生物活性化合物的新型前体。然而，串联全氟酰化得到4，6-双（全氟烷基）-2H-吡喃，而不是2，4-二烯基酮。综上所述，我们所合成的几种2，4，6-庚三烯醛类化合物，都具有很高的光敏性，可以合成新的双环化合物。特别地，2-氰基庚三烯醛的制备导致直接形成氧杂双环化合物，而不是三烯醛。

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.