Synthetic studies on the starfish alkaloid imbricatine. A chiral synthesis of tri-O-methylimbricatine

Article abstract of DOI:10.1016/S0040-4020(99)00199-4

A detailed account is given of the chiral synthesis of tri-O- methylimbricatine (3), the triO-methyl derivative of the structurally unique benzyltetrahydroisoquinoline alkaloid imbricatine (2) isolated from the starfish Dermasterias imbricata. The route begins with the asymmetric synthesis of the sulfur-containing D-phenylalanine derivative (R)-11a and includes its conversion into the cis-benzyltetrahydroisoquinoline moiety 26a possessing the thiol group and construction of the 5-arylthio-3-methyl-L- histidine portion. The correctness of the structure and absolute configuration proposed for imbricatine has been unequivocally confirmed as a result of the present synthesis.