Synthesis of Oxepanes and <i>trans</i>-Fused Bisoxepanes via Biomimetic, <i>endo</i>-Regioselective Tandem Oxacyclizations of Polyepoxides
作者:Frank E. McDonald、Xia Wang、Bao Do、Kenneth I. Hardcastle
DOI:10.1021/ol0064009
日期:2000.9.1
This communication describes the first examples of tandem endo-regioselective and stereospecific oxacyclizations of 1,5-diepoxides to oxepane products and a similar tandem oxacyclization of 1,5,9-triepoxides to fused bisoxepane cyclic carbonates. A mechanism for these biomimetic oxacyclizations is proposed in which the epoxides act as both electrophilic and nucleophilic reaction partners.
Endo-Oxacyclizations of Polyepoxides: Biomimetic Synthesis of Fused Polycyclic Ethers
作者:Frank E. McDonald、Fernando Bravo、Xia Wang、Xudong Wei、Motoki Toganoh、J. Ramón Rodríguez、Bao Do、Wade A. Neiwert、Kenneth I. Hardcastle
DOI:10.1021/jo0110092
日期:2002.4.1
to open another epoxide that is activated as an electrophile by the Lewis acid. These oxacyclizations proceed stereospecifically with inversion of configuration upon opening of each epoxide to provide trans-fused polycyclic products. The oxacyclization cascade is terminated by a tethered nucleophile, which may be the carbonyl oxygen of a ketone, ester, or carbonate, or a trisubstituted alkene. The best
Gold‐catalyzed <i>endo</i>‐selective Ring‐opening of Epoxides and its Application in Construction of Poly‐ethers
作者:Kehuan Wu、Kaiwen Kang、Dan Liu、Chiyue Zhang、Xinyu Wang、Miaocheng Zhang、Qi Li
DOI:10.1002/chem.202400234
日期:2024.4.11
Abstract
Tetrahydropyran and tetrahydropyran‐fused poly‐ethers scaffolds are found in many classes of natural products and medicinally relevant small molecules. Here we describe a catalytic system for 6‐endo selective ring‐opening of epoxides by Au(I) or Au(III) catalyst that provides rapid access to various tetrahydropyran‐derived motifs. It also could efficiently construct the subunits of marine ladder‐like poly‐ethers through emulating the Nakanishi's hypothesis on the biosynthesis of these toxins. The synthetic utility of this method is also demonstrated in the preparation of the tricyclic core of tetrahydropyran‐containing macrolide natural products lituarines A−C.