Studies on monoterpene glucosides and related natural products. XLV. Synthesis of 13C-labeled acyclic monoterpenes for studies on the mechanism of the iridane skeleton formation in the biosynthesis of iridoid glucosides.
作者:SHINICHI UESATO、KOJI KOBAYASHI、HIROYUKI INOUYE
DOI:10.1248/cpb.30.927
日期:——
For studies on the cyclopentane ring formation from acyclic monoterpenes in the biosynthesis of iridoid glucosides, the following 13C-labeled precursors of the acyclic monoterpene series were synthesized : [9-13C]-and [4-13C]-10-hydroxygeraniol (9), [2-13C]-9, 10-dihydroxygeraniol (10), (R)-(+)-and (S)-(-)-[9-13C]-10-hydroxycitronellol ((R)-(+)-and (S)-(-)-8), (R)-(+)-and (S)-(-)-[8-13C]-9, 10-dihydroxycitronellol ((R)-(+)-and (S)-(-)-11).
A copper-promoted flexible synthesis of cyclobutenes carrying simple alkyl chains, enabling even the most hindered nucleophiles to be employed, has been developed. The versatility of this approach was exemplified by a short total synthesis of ieodomycin D and a straightforward preparation of the southeastern fragment of macrolactin A. The latter features a late-stage, double cyclobutene electrocyclic
已经开发出一种由铜促进的带有简单烷基链的环丁烯的灵活合成,即使是最受阻的亲核试剂也能被使用。这种方法的多功能性体现在碘霉素 D 的短全合成和大环乳素 A 东南片段的直接制备。后者具有后期双环丁烯电环开环,可直接提供定义几何形状的双二烯.
Dialkyl Ether Formation at High-Valent Nickel
作者:Franck Le Vaillant、Edward J. Reijerse、Markus Leutzsch、Josep Cornella
DOI:10.1021/jacs.0c07381
日期:2020.11.18
remains stable at lowtemperatures, thus permitting its characterization by NMR, EPR, X-ray, and HRMS. At higher temperatures (>−10 °C), such bimetallic intermediate thermally decomposes to afford large amounts of elimination products together with iodoalkanols. Observation of the latter suggests that a C(sp3)–I bond reductive elimination occurs preferentially to any other challenging C–O bond reductive elimination
Efficient preparations of 8- and 9-membered cyclic ethers
作者:Larry E. Overman、Todd A. Blumenkopf、Armando. Castaneda、Andrew S. Thompson
DOI:10.1021/ja00272a062
日期:1986.6
Syntheses de tetrahydro-3,4,7,8 oxocinnes et d'hexahydro-2,3,4,5,8,9 oxoninnes par cyclisation avec SnCl 4 d'alcene-5yl- et alcene-6yl methoxyethoxymethyl ethers
合成四氢-3,4,7,8 oxocinnes et d'hexahydro-2,3,4,5,8,9 oxoninnes par 环化 avec SnCl 4 d'alcene-5yl- et alcene-6yl 甲氧基乙氧基甲基醚
Regioselective ring opening of unsymmetrical cyclic ethers with the A1C13-NaI-acetonitrile system: Application to hydroxylation of ent-kaurene.
Unsymmetrically substituted 5-membered cyclicethers were effectively cleaved with the A1C13-NaI-CH3CN system at the less hindered carbon atom to afford δ-iodoalcohols. Conversion of ent-kaurene to ent-14α- and ent-12β-hydroxykaurene was achieved through the ringopening of the cyclicether with the present system as a key step.