An Enantioselective Version of the AB + D --> ABCD-Type Stereoid Total Synthesis

Article abstract of DOI:10.1016/S0040-4039(00)92517-6

Diene 1 and dienophile 4a in a Diels/Alder reaction mediated by a chiral ligand-modified Lewis acid enantioselectively furnish adduct 5a (chem. yield: 64percent; e.e: 73percent), which after partial deoxygenation and final enantioselection by recrystallization affords 5b.The latter compound can easily be converted via Torgov's pentaenone 6a into estrogens or progestogens. Key Words: stereoid total synthesis, enantioselective Lewis acid-mediated Diels/Alder reaction