インカビラテインおよび関連アルカロイドの全合成

抄録

The first total syntheses of new monoterpene alkaloids (-)-incarvilline, (+)-incarvine C, and (-)-incarvillateine, corresponding to the natural enantiomers, have been accomplished. The strategy for the synthesis of these natural products utilized 6-epi-incarvilline as a common precursor, which was assembled by a three-component coupling reaction using (4S)-4-siloxy-2-cyclopenten-1-one to construct an appropriately trisubstituted cyclopentanone, followed by ring closure to the cis-perhydro-2-pyrindine skeleton by means of a reductive Heck-type reaction. An alternative ring closure to the cis-perhydro-2-pyrindine skeleton was also carried out employing intramolecular enone-olefin [2+2] photocycloaddition. Furthermore, topochemically controlled [2+2] photodimerization of ferulic acid derivatives in the solid state for the stereospecific construction of a 1,2,3,4-tetrasubstituted cyclobutane ring was investigated as a means to access (-)-incarvillateine.