The first total synthesis of lamellarin α 20-sulfate, a selective inhibitor of HIV-1 integrase

The first total synthesis of lamellarin α 20-sulfate (1), a selective inhibitor of HIV-1 integrase, has been completed. The lamellarin α core in which 13-OH and 20-OH were differentially protected by isopropyl and benzyl groups, respectively, was constructed by using Hinsberg-type pyrrole synthesis and Suzuki–Miyaura coupling as the key reactions. The 20-sulfate was prepared by a sequence including debenzylation of 20-OBn, 2,2,2-trichloroethylsulfation of the resulting 20-OH, deprotection of 13-Oi-Pr, and final reductive cleavage of the 2,2,2-trichloroethyl ester.