Highly Chemoselective Reduction of Amides (Primary, Secondary, Tertiary) to Alcohols using SmI<sub>2</sub>/Amine/H<sub>2</sub>O under Mild Conditions
作者:Michal Szostak、Malcolm Spain、Andrew J. Eberhart、David J. Procter
DOI:10.1021/ja412578t
日期:2014.2.12
Highly chemoselective direct reduction of primary, secondary, and tertiary amides to alcohols using SmI2/amine/H2O is reported. The reaction proceeds with C–N bond cleavage in the carbinolamine intermediate, shows excellent functional group tolerance, and delivers the alcohol products in very high yields. The expected C–O cleavage products are not formed under the reaction conditions. The observed
A Polar Effects Controlled Enantioselective 1,2-Chlorine Atom Migration via a Chlorine-Bridged Radical Intermediate
作者:Eng Wui Tan、Bun Chan、Allan G. Blackman
DOI:10.1021/ja011129r
日期:2002.3.1
An enantioselective 1,2-chlorine atom migration was observed in the tributyltin hydride reduction of various dihalogenated dihydrocinnamic acid derivatives. It is proposed that the reduction involves the formation of a chlorine-bridged radical intermediate, followed by hydrogen atom transfer to either the beta- or the alpha-carbon. The product distribution is affected by electron-withdrawing groups
Radical α,β-Dehydrogenation of Saturated Amides via α-Oxidation with TEMPO under Transition Metal-Free Conditions
作者:Mei-Mei Wang、Guo-Hui Sui、Xian-Chao Cui、Hui Wang、Jian-Ping Qu、Yan-Biao Kang
DOI:10.1021/acs.joc.9b00872
日期:2019.6.21
A transitionmetal-free radical process for the selective α,β-dehydrogenation of saturated amidesunder mild conditions is developed. Utilizing radical activation strategy, the challenging issue associated with the low α-acidity of amides is resolved. For the first time, α,β-unsaturated Weinreb amides and acrylamides could be efficiently prepared directly from corresponding saturated amides. Mechanistic
We developed a new transition-metal-free intermolecular Claisenrearrangement process to introduce allyl and allenyl groups into the α position of tertiary amides. In this transformation, amides were activated by trifluoromethanesulfonic anhydride to produce the keteniminium ion intermediates that exhibit strong electrophilic activity. This atom-economical process delivers α position-modified amides