Palladium-Catalyzed Asymmetric Synthesis of 2-Alkynyl Oxacycles
作者:David S. B. Daniels、Amber L. Thompson、Edward A. Anderson
DOI:10.1002/anie.201105720
日期:2011.11.25
cyclizations of cyclic and acyclic propargylic carbonates give 2‐alkynyl oxacycles. The reactions proceed with very high stereoselectivity for both syn‐ and anti‐disubstituted furans and pyrans, and with exceptional regioselectivity. In addition, two‐directional cyclizations of bis‐propargylic carbonate substrates yield bifurans with complete stereocontrol for all diastereomers.
Site- and Enantiodifferentiating C(sp<sup>3</sup>)–H Oxidation Enables Asymmetric Access to Structurally and Stereochemically Diverse Saturated Cyclic Ethers
作者:Shutao Sun、Yiying Yang、Ran Zhao、Dongju Zhang、Lei Liu
DOI:10.1021/jacs.0c09636
日期:2020.11.11
A manganese-catalyzed site- and enantiodifferentiating oxidation of C(sp3)-H bonds in saturated cyclic ethers has been described. The mild and practical method is applicable to a range of tetrahydrofurans, tetrahydropyrans, and medium-sized cyclic ethers with multiple stereocenters and diverse substituent patterns in high efficiency with extremely efficient site- and enantiodiscrimination. Late-stage