Synthesis of hydantocidin and C-2-thioxo-hydantocidin.

Hydantocidin, a naturally occurring strong herbicide, was synthesized in an overall yield of 35.2%, with the accompanying 1'-epi-hydantocidin in overall 9.6% yield from 2,3-O-isopropylidene-D-ribono-1,4-lactone. C-2-thioxo-hydantocidin and its spiro-epimer were also synthesized in an overall yield of 14.4% and 8.5%, respectively.