Total Synthesis and Structure Assignment of Papuamide B,A Potent Marine Cyclodepsipeptide with Anti-HIV Properties

摘要

Papuamides A (1a) and B (1b) (Scheme 1) are two novel cyclic depsipeptides that were isolated from Papua New Guinea collections of the marine sponges Theonella mirabilis and Theonella swinhoei.Both compounds exhibit a strong inhibitory effect on the infection of human T-lymphoblastoid cells by HIV-1_(RF) in vitro,with an EC50 value of about 4 ng mL~(-1).Similar biological activities were also observed for other cyclic depsipeptides isolated from different marine sponges,namely:callipeltin A,neamphamide A,and mirabamides A-D.Given this background,it is not surprising that recent intensive efforts have been directed towards gaining synthetic access to these natural products.These efforts have led to the successful establishment of the stereochemistry of some sterogenic centers within this class of compounds.However,none of these molecules have yet been assembled.Herein,we report our synthetic strategy towards papuamide B.