New total synthesis of (+)-cystothiazole A based on palladium-catalyzed cyclization–methoxycarbonylation

Palladium-catalyzed cyclization-methoxycarbonylation of (2R,3S)-3-methylpenta-4-yne-1,2-diol () derived from (2R,3S)-epoxy butanoate 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 A ().