(+)-Cystothiazole G: isolation and structural elucidation

Palladium-catalyzed cyclization-methoxycarbonylation of (2R,3S)-3-methylpent-4-yne-1,2-diol () derived from (2R,3S)-epoxybutanoate followed by methylation gave the tetrahydro-2-furylidene acetate , which was converted to the left-half aldehyde . A Wittig reaction between and the phosphoranylide derived from the bithiazole-type phosphonium iodide using lithium bis(trimethylsilyl)amide afforded the (+)-cystothiazole G (), whose spectral data were identical with those of the natural product . Thus, the stereochemistry of cystothiazole G () was proved to be (4R,5S,6(E)).