Hypervalent (<i>tert</i>-Butylperoxy)iodanes Generate Iodine-Centered Radicals at Room Temperature in Solution: Oxidation and Deprotection of Benzyl and Allyl Ethers, and Evidence for Generation of α-Oxy Carbon Radicals
reductive deprotection. Oxidation with 1a occurs readily with C−H bonds activated by both enthalpic effects (benzylic, allylic, and propargylic C−H bonds) and/or polar effects (α-oxy C−H bonds), generating α-oxy carbon-centered radicals, which can be detected by nitroxyl radical trapping. Measurement of the relative rates of oxidation for a series of ring-substituted benzyl n-butyl ethers 2d and 2p−s
Metal-Catalyzed Silylene Insertions of Allylic Ethers: Stereoselective Formation of Chiral Allylic Silanes
作者:Laura E. Bourque、Pamela A. Cleary、K. A. Woerpel
DOI:10.1021/ja073758s
日期:2007.10.1
Silylene insertion into allylicethers occurs suprafacially to provide enantioenriched allylic silanes and disilanes. Silylene insertion to a variety of protected allylic alcohols utilizing silver- and copper-mediated conditions proved to be a general method for allylic silane formation. Allylic disilanes reacted similarly to allylic silanes, undergoing both annulation and allylation reactions.
Catalytic Allylic Oxidation of Cyclic Enamides and 3,4-Dihydro-2<i>H</i>-Pyrans by TBHP
作者:Yang Yu、Ranad Humeidi、James R. Alleyn、Michael P. Doyle
DOI:10.1021/acs.joc.7b01163
日期:2017.8.18
intermediate allylic free radical two sites for oxidative product formation are possible, and the selectivity of the oxidative process varies with the heteroatom when R = H. Cyclic enamides produce 4-piperidones in good yields when R = alkyl or aryl, but oxidation of 2H-pyrans also gives alkyl cleavage products. Alternative catalysts for TBHP oxidations show comparable selectivities but give lower product