[2+2+2]‐Cycloaddition of 4‐Hydroxy‐Substituted Enediynes to 2‐Hydroxy‐Substituted Decahydrophenanthrenes

Abstract

Abstract Enediynes rac ‐ 4 were prepared in seven steps with an overall yield of 31% starting from 4‐pentyn‐1‐ol ( 5 ). A cobalt mediated [2+2+2]‐cycloaddition of these enediynes and subsequent removal of the metal fragment afforded the decahydrophenanthrenes rac ‐ 3 / 13 in 37−56% yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)