Collect. Czech. Chem. Commun. 1989, 54, 1327-1335

Spontaneous transannular reaction in Δ9-unsaturated A-homo-B,19-dinorsteroids

Alexander Kasal and Jaroslav Zajíček

Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


The epoxidation of 3β-hydroxy derivatives of Δ9-unsaturated A-homo-B,19-dinorsteroids (type I-IV) proceeds with spontaneous participation of the 3β-hydroxyl under formation of transannular 9α-hydroxy-3β,10β-oxides IX, X, XV and XVII. Epoxidation of the corresponding esters V-VIII affords predominantly 9α,10α-epoxides XIV, XVI, XVIII and XIX which, after hydrolysis of the ester groups are also converted into the transannular 3β,10β-oxides of the type IX.