198754-78-8Relevant articles and documents
Total synthesis of polycavernoside A, a lethal toxin of the red alga Polycavernosa tsudai
Blakemore, Paul R.,Browder, Cindy C.,Hong, Jian,Lincoln, Christopher M.,Nagornyy, Pavel A.,Robarge, Lonnie A.,Wardrop, Duncan J.,White, James D.
, p. 5449 - 5460 (2007/10/03)
Two approaches to the synthesis of the aglycon 120 of polycavernoside A (1) were developed, only one of which was completed. The successful "second-generation" route assembled the aglycon seco acids 102 and 106 via Nozaki-Hiyama-Kishi coupling of aldehyde 70, prepared from methyl (S)-3-hydroxy-2-methylpropionate (72) and (S)-pantolactone (73), with vinyl bromide 71. The latter was obtained from a sequence which commenced from the silyl ether 24 of 3-hydroxypropionaldehyde and entailed cyclization of (Z)-ζ-hydroxy-α,β-unsaturated ester 82. Regioselective Yamaguchi lactonization of trihydroxycarboxylic acids 102 and 106 and subsequent functional-group adjustments led to macrolactone 120, to which the fucopyranosylxylopyranoside moiety was attached. Stille coupling of the glycosidated aglycon 128 with dienylstannane 129 furnished polycavernoside A in a synthesis for which the longest linear sequence was 25 steps. The overall yield to lactone 120 was 4.7%.
Intramolecular palladium catalyzed alkoxy carbonylation of 6-hydroxy-1- octenes. Stereoselective synthesis of substituted tetrahydropyrans
White, James D.,Hong, Jian,Robarge, Lonnie A.
, p. 1463 - 1466 (2007/10/03)
The reaction of hydroxy alkenes 5, 7, and 8 with CO and MeOH in the presence of PdCl2 and CuCl2 gave tetrahydropyrans 9, 11, and 12, respectively. Yields were dependent upon the configuration of substituents in the hydroxy alkene; in all cases, the tetrahydropyran was produced with 2,6- cis configuration.
