Acetylenic bond participation in biomimetic polyene cyclizations. Model studies directed toward the synthesis of 20-keto steroids. Synthesis of dl-progesterone and dl-. …

MB Gravestock, WS Johnson, BE McCarry…

Index: Gravestock,M.B. et al. Journal of the American Chemical Society, 1978 , vol. 100, # 13 p. 4274 - 4282

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Citation Number: 65

Abstract

Abstract: The object of this study was to examine the possibility that an appropriately disposed acetylenic bond would participate in biomimetic polyene cyclizations so as to generate the five-membered D ring of steroids. Treatment of the dienynol 3 (synthesized as shown in Scheme I) with anhydrous formic acid in pentane for 15 min at 20" C resulted in an 82% yield of the bicyclic enol formate 19. Hydrolysis of 19 gave a mixture of the ketone 21 ...

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