catalytic methods for the oxidative furan-recyclizations remain scarcely investigated. Given this, we report a means of manganese-catalyzed oxidations of furan with low loading, achieving the Achmatowiczrearrangement in the presence of hydrogen peroxide as an environmentally benign oxidant under mild conditions with wide functional group compatibility.
Alcohol dehydrogenases can act as powerful catalysts in the preparation of opticallypure γ-hydroxy-δ-lactones by means of an enantioconvergent dynamic redox isomerization of readily available Achmatowicz-type pyranones. Imitating the traditionally metal-mediated "borrowing hydrogen" approach to shuffle hydrides across molecular architectures and interconvert functional groups, this chemoinspired and
A TiCl4-promoted cascade formal [3 + 2] cycloaddition/double ring-opening/chlorination of 2-furylcyclobutanols with alkyl or aryl azides is described. This highlyefficient transformation involves the formation/cleavage of several C–N, C–Cl, C–C, and C–O bonds in a single operation. It enables the quick construction of trisubstituted 1,2,3-triazoles with an (E)-enone moiety and a 3-chloropropyl unit
We report the first terminal trifluoromethylation at aryl and alkyl ketones’ γ, δ, ε, or more remote sites via the selective C–C bond cleavage of cycloalkanols. The noncovalent interactions between alcohols and hypervalent iodines(III) reagents were disclosed to activate both alcohols and the Togni I reagent in the dual photoredox/copper catalysis for the transformation. This reaction was scalable
我们报告了通过环烷醇的选择性 C-C 键断裂在芳基和烷基酮的 γ、δ、ε 或更远的位点发生的第一个末端三氟甲基化。公开了醇和高价碘 (III) 试剂之间的非共价相互作用,以在双光氧化还原/铜催化转化中激活醇和 Togni I 试剂。该反应可扩展到克级合成,适用于结构复杂的类固醇三氟甲基化,并可扩展到五氟乙基化。
Direct Syntheses of Spiro- and Fused-Hydrofurans by a Tunable Tandem Semipinacol Rearrangement/Oxa-Michael Addition Protocol
作者:Bao-Sheng Li、Wen-Xing Liu、Qing-Wei Zhang、Shao-Hua Wang、Fu-Min Zhang、Shu-Yu Zhang、Yong-Qiang Tu、Xiao-Ping Cao
DOI:10.1002/chem.201300205
日期:2013.4.22
one‐pot reaction has been developed involving a tandemsemipinacolrearrangement/oxa‐Michael addition sequence in which the in situ generated ketol diene intermediate can be transformed specifically to either the spiro‐ or fused‐dihydrofuran products (see scheme). This one‐pot tandem reaction represents a general synthetic methodology for the syntheses of the two different kinds of furan derivatives