17 Illudinsの合成-II

概要

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The compound XII, which has the unique non-isoprenoid skeleton and characteristic structural features of illudins, has been synthesized. The Michael reaction of IV and X was highly stereo-selective, a single product XI being obtained although eight racemic isomers are possible. The newly formed bond of XI was reasoned to be trans-oriented to the acetoxyl group on the five membered ring. The acetoxyl group at C_4 was introduced by the Pummerer reaction of XI. Treatment of XI with acetic anhydride-pyridine for a week at room temperature gave the expected product XIII. Only a single compound XIII was obtained as a Pummerer reaction product in spite of the possible existence of two stereoisomers. The compound XIII was converted to XIV by reduction with amalgamated aluminum and then to XVI through hydrolysis of the ketal group followed by intramolecular aldol condensation. NMR spectrum of XVI indicated the configurations at C_<3,4,9> as shown in Fig. 2. Attack of the Grignard reagent to XVI was also stereoselective and only one crystalline product was obtained. Total synthesis of illudins through the compounds described above is now under investigation.
天然有機化合物討論会の論文
1967-09-25