title: A Synthetic Strategy for Saxitoxin Skeleton by a Cascade Bromocyclization: Total Synthesis of (+)-Decarbamoyl-α-saxitoxinol.
abstract: A new synthetic strategy for the formation of the ABC tricyclic framework of saxitoxin was developed. The BC ring moiety, including a spiro-aminal structure, was first constructed stereoselectively by a newly designed cascade bromocyclization of a readily available internal alkyne bearing guanidine and urea. The A ring was then synthesized by a guanylation of a cyclic urea, easily prepared via the oxidative cleavage of the diol of the cascade product, followed by addition of cyanide. This strategy enables the concise stereocontrolled total synthesis of (+)-decarbamoyl-α-saxitoxinol, which is a naturally occurring saxitoxin analogue.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University , Chikusa, Nagoya 464-8601, Japan.
authors.forename: Sohei
authors.initials: S
authors.lastname: Ueno
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University , Chikusa, Nagoya 464-8601, Japan.
authors.forename: Atsuo
authors.identifier: 0000-0002-0025-0523
authors.initials: A
authors.lastname: Nakazaki
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University , Chikusa, Nagoya 464-8601, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Nishikawa