The novel alkaloid calycotomine, a 1-hydroxymethylenetetrahydroisoquinoline, has been synthesized from l-methyl-3,4-dihydroisoquinoline via the 2-benzyloxycarbonyl enamide derivative. Oxidation of the enamide with osmium tetroxide results in bis-hydroxylation and ring opening to form hydroxyacetophenone carbamates. Hydrogenation results in reclosure of the isoquinoline ring and further reduction yielding 1-hydroxymethylenetetrahydro-isoquinolines. © 1987.