Intramolecular Reactions of Metal Carbenoids with Allylic Ethers: Is a Free Ylide Involved in Every Case?
作者:J. Stephen Clark、K. Emelie Hansen
DOI:10.1002/chem.201304054
日期:2014.4.25
reactions of the 13C‐labelled diazo carbonyl substrates 18* and 19* were performed. Results obtained from copper‐ and iridium‐catalyzed reactions of the 13C‐labelled α‐diazo β‐keto ester 19* indicate that either or both of these reactions do not proceed via a free oxonium ylide but instead follow a competing non‐ylide route that delivers apparent [2,3]‐sigmatropicrearrangement products. In the case
[1,2]- or [2,3]-Rearrangement of Onium Ylides of Allyl and Benzyl Ethers and Sulfides via in Situ-Generated Iodonium Ylides
作者:Graham K. Murphy、F. G. West
DOI:10.1021/ol061772o
日期:2006.9
Iodoniumylides, generated in situ with bisacetoxyiodobenzene, are converted to allyl- or benzyl-substituted oxonium or sulfonium ylides via rhodium- or copper-catalyzed carbene transfer. Except for the S-benzyl example, the resulting ylides undergo rearrangement to the corresponding 2-substituted heterocycles. This demonstrates the first use of iodoniumylides as diazoketone surrogates for the generation
Rh(II)/Pd(0) Dual Catalysis: Regiodivergent Transformations of Alkylic Oxonium Ylides
作者:Zi-Sheng Chen、Xiao-Yan Huang、Ling-Hang Chen、Jin-Ming Gao、Kegong Ji
DOI:10.1021/acscatal.7b02909
日期:2017.11.3
A Rh(II)/Pd(0) dual-catalysis strategy that promotes the regio-divergent transformations of alkylic oxonium ylides from α-diazo-β-ketoesters has been developed. Polyfunctionalized dihydrofuran-3-ones with an O-substituted quaternary carbon center and 2,3-disubstituted benzofurans can be selectively obtained in good to excellent yields at room temperature via one-pot synthesis. The reaction mechanism