title: Development of a Divergent Synthetic Route to the Erythrina Alkaloids: Asymmetric Syntheses of 8-Oxo-erythrinine, Crystamidine, 8-Oxo-erythraline, and Erythraline.
abstract: A general synthetic methodology toward the erythrina alkaloids has been developed. Inspired by a proposed biosynthetic mechanism, the medium-sized chiral biaryl lactam was asymmetrically transformed into the common core A-D rings by a stereospecific singlet oxygen oxidation of the phenol moiety, followed by a transannular aza-Michael reaction to the dienone functionality. The late-stage manipulation of the oxidation and oxygenation states of the functional groups on the peripheral moieties enabled the flexible syntheses of the erythrina alkaloids.
authors.affiliation: Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Hirotatsu
authors.initials: H
authors.lastname: Umihara
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8601, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Yoshino
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8601, Japan.
authors.forename: Jun
authors.identifier: 0000-0002-4023-4640
authors.initials: J
authors.lastname: Shimokawa
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8601, Japan. kitamura@os.rcms.nagoya-u.ac.jp.
authors.forename: Masato
authors.identifier: 0000-0002-0543-8795
authors.initials: M
authors.lastname: Kitamura
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8601, Japan. fukuyama@ps.nagoya-u.ac.jp.
authors.forename: Tohru
authors.initials: T
authors.lastname: Fukuyama
keywords: alkaloids; annulations; atropisomerism; chirality; total synthesis