Determination of the absolute structure of (+)-cystothiazole B.
Palladium-catalyzed cyclization-methoxycarbonylation of (2R,3S)-3-methylpenta-4-yne-1,2-diol (6) derived from (2R,3S)-epoxy butanoate 5, followed by methylation, gave the tetrahydro-2-furylidene acetate (-)-7, which was converted to the left-half aldehyde (+)-3. A Wittig reaction between (+)-3 and the phosphoranylide derived from the bithiazole-type phosphonium iodide 4 using lithium bis(trimethylsilyl)amide afforded (+)-cystothiazole B (2), the spectral data of which were identical to those of the natural product (+)-2. Thus the stereochemistry of cystothiazole B (2) was confirmed to be [4R, 5S, 6(E)].
Sasaki
Takamitsu
T
School of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
Kato
Keisuke
K
Akita
Hiroyuki
H
D015394:Molecular Structure; D013844:Thiazoles / Q000737:chemistry*
D013844:Thiazoles; C112183:cystothiazole B