Abstract The synthesis and cationic cyclization of 2-[6-(3-methoxyphenyl)-2-methyl-(E)-3- hexenyl]-3-methyl-2-cyclopentenol (12) was investigated. The major cyclization products were 1-and 3-methoxy-11α, 17-dimethyl-1, 3, 5 (10), 13 (17)-gonatetraene (14a and 15a) indicating a high degree of asymmetric induction by the pro-C (11) chiral centre. Compound 15a was converted into DL-11α-methylestrone methyl ether (18).
