Enantioselective synthesis of the Prelog-Djerassi lactonic acid via group-selective aldolization/desymmetrization of a meso dialdehyde with a chiral N-propionylsultam

Article abstract of DOI:10.1016/S0040-4039(96)02408-2

The group-selective aldolization/desymmetrization of meso dialdehyde 5 with a borylenolate derived from N-propionylbornanesultam ent-2 yields very efficiently lactols 6 with simultaneous generation of four stereogenic centers. Oxidation (6→7) followed by saponification of the sultam moiety (7→4) provided the Prelog-Djerassi lactonic acid 4 in a three step sequence in 61-71% overall yield.