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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(4):964-968
We report the total syntheses of daphenylline ( 1 ), daphnipaxianine A ( 5 ), and himalenine D ( 6 ), three Daphniphyllum alkaloids from the calyciphylline A subfamily. A pentacyclic triketone was prepared by using atom‐transfer radical cyclization and the Lu [3+2] cycloaddition as key steps. Inspired by the proposed biosynthetic relationship between 1 and another calyciphylline A type alkaloid, we developed a ring‐expansion/aromatization/aldol cascade to construct the tetrasubstituted benzene moiety of 1 . The versatile triketone intermediate was also elaborated into 5 and 6 through a C=C bond migration/aldol cyclization approach. 相似文献
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Hirotatsu Umihara Tomomi Yoshino Jun Shimokawa Masato Kitamura Tohru Fukuyama 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(24):7029-7032
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. 相似文献
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