A General Method for Convergent Synthesis of Polycyclic Ethers Based on Suzuki Cross-Coupling: Concise Synthesis of the ABCD Ring System of Ciguatoxin
摘要:
[GRAPHICS]A general method for convergent assembly of polyether structure has been developed based on palladium(0)-mediated Suzuki cross-coupling reaction of alkylboranes with cyclic ketene acetal phosphates. The present method allowed for coupling of medium-sited ether rings and thus a concise synthesis of the ABCD ring system of ciguatoxins has been achieved.
The stereoselectivesynthesis of the WXYZA'-ring system of maitotoxin has been accomplished via a linear synthetic approach, in which key reactions were SmI 2-induced cyclization of beta-alkoxyacrylate for the construction of the A'-, Y-, and X-rings and 6- endo cyclization of hydroxy vinylepoxide for that of the Z- and W-rings.
Synthesis of Luffarin L and 16-<i>epi</i>-Luffarin L Using a Temporary Silicon-Tethered Ring-Closing Metathesis Reaction
作者:Aitor Urosa、Isidro S. Marcos、David Díez、José M. Padrón、Pilar Basabe
DOI:10.1021/acs.joc.5b00876
日期:2015.6.19
The first synthesis of luffarin L (1) and 16-epi-luffarin L (2) by a silicon-tethered ring closing metathesis as a key step has been achieved. The stereochemistry and absolute configuration of the natural sesterterpenolide luffarin L (1) and a new route for the stereoselective synthesis of sesterterpenolides with a luffarane skeleton have been established.
Total Synthesis of Spiroketal Alkaloids Lycibarbarines A–C
作者:Eilidh G. Young、Phillip S. Grant、Daniel P. Furkert、Margaret A. Brimble
DOI:10.1021/acs.orglett.3c00902
日期:2023.4.28
Lycibarbarines A–C are spirocyclic alkaloids with a unique tetracyclic framework, consisting of tetrahydroquinoline and spiro-fused oxazine–sugar spiroketal subunits. The first total syntheses of lycibarbarines A–C were achieved over 10 steps (longest linear sequence) each. Through this work, it was discovered that the spiroketal unit of lycibarbarines A–C exhibits unusually high resistance to acid-mediated