Access toward steroid skeleton and its derivatives via copper‐catalyzed intramolecular cyclization: A short synthesis of estradiol and estrone

An efficient method towards the synthesis of [6,6,6,5] tetracyclic fused ring steroid skeletons (8 a–i) has been designed through copper catalyzed [4+2] cycloaddition reaction of 1,6-enyne-al (7 a–i) which was prepared via sonogashira reaction between aromatic substrates (6 a–e) and enyne fragments (5 a–b). The compound 8 a was further utilized to synthesize estradiol and Estrone.

Abstract

A practical and efficient approach leading to [6,6,6,5] tetracyclic fused ring steroid skeletons (8 a–i) has been designed through copper catalyzed intramolecular [4+2] cycloaddition reaction of enyne-carbonyl substrates (7 a–i). The compound 8 a having OMe group at aromatic ring was further utilized to synthesize estradiol and Estrone.

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