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
Reduction of Acetals with Samarium Diiodide in Acetonitrile in the Presence of Lewis Acids.
作者:Munetaka KUNISHIMA、Daisuke NAKATA、Takayuki SAKUMA、Kazuhiro KONO、Shoichi SATO、Shohei TANI
DOI:10.1248/cpb.49.97
日期:——
Transformation of acetals into ethers by partial reduction using a samarium diiodide-Lewis acids-acetonitrile system is described. The reaction with aromatic acetals occurred in good yields in the presence of aluminum chloride (2 eq) whereas the corresponding aliphatic, vinylic, and alkynyl derivatives did not afford ethers under the same conditions. Beta-elimination to give an enol ether becomes predominant