Synthesis of a Prenylated and Immunosuppressive Marine Galactosphingolipid with Cyclopropane-Containing Alkyl Chains: (2S,3R,11S,12R,2′′′R,5′′′Z,11′′′S,12′′′R)-Plakoside A and Its (2S,3R,11R,12S,2′′′R,5′′′Z,11′′′R,12′′′S) Isomer
摘要:
Plakoside A (1) {(2S,3R,11R*,12S*)-2-[(2'''R,5'''Z,11'''R*, 12'''S*)-2"'-hydroxy-11"',12"'-methylene-5"'-docosenamido] -1-O-[2'-O-(3"-methyl-2"-butenyl)-beta -D-galactopyranosyl]-11,12-methylene-1,3 -docosanediol} is a prenylated galactosphingolipid isolated as an immunosuppressant from the marine sponge Plakortis simplex. (2S,3R,11S,12R,2'''R,5'''Z,11'''S,12'''R)-Plakoside A (1) has been synthesized by combining the sphingosine part 16, the alpha -hydroxy acid part 28, and the prenylated sugar part 33. (2S,3R,11R,12S,2'''R,5'''Z,11'''R, 12'''S)-Plakoside A (1') has also been synthesized.
Synthesis of (2 S ,3 R ,11 S ,12 R ,2‴ R ,11‴ S ,12‴ R )-plakoside A, a prenylated and immunosuppressive marine galactosphingolipid with cyclopropane-containing alkyl chains
摘要:
Plakoside A (1) is a prenylated galactosphingolipid isolated from the marine sponge Plakoartis simplex and is strongly immunosuppressive without cytotoxicity. (2S,3R,11S,12R,2"'R,11"'S, 12'''R)-plakoside A (1) was synthesized by combining sphingosine part 16, alpha -hydroxy acid part 24 and prenylated sugar part 29. (C) 2001 Elsevier Science Ltd. All rights reserved.
The total synthesis of plakosides A (1) and B (2), and their designed analogs 3 – 10 was accomplished. The convergent strategy employed involved construction of the individual building blocks employing the Sharpless asymmetric dihydroxylation and the Charette asymmetric cyclopropanation reactions to introduce the desired configuration, followed by their couplings and final elaboration. Thus, key intermediates