Total Synthesis of Tautomycin

Article abstract of DOI:10.1021/jo00121a026

A convergent stereocontrolled synthesis of the antifungal antibiotic tautomycin, a potent protein phosphatases inhibitor, has been achieved first via key aldol coupling of two large subunits, a right-hand C1-C21 ketone and a left-hand aldehyde (left from C22).The C1-C10 segment was synthesized through a remote stereochemical control process using a spiroketal template.After joining with the C11-C18 segment, the spiroketal moiety was selectively constructed.Then the right-hand C1-C21 ketone was synthesized via Roush asymmetric crotylboration.The left-hand aldehyde was prepared from a C21-C26 segment and a dialkylmaleic anhydride segment.Completely stereoselective assemblage of the two subunits, the right-hand and the left-hand, was achieved by employing the Mukaiyama aldol reaction.Further functional group manipulation including desilylation, oxidation at C2, and deprotection of tert-butyl ester with concomitant anhydride formation provided tautomycin which was identical with the natural product.As a preliminary study, derivatizations and degradation of the natural product were also examined to support the total synthesis.