The selective addition of organomagnesium reagents to 2,4,6‐trichlorophenyl isocyanide leading to magnesiated aldimines is reported. These aldimines react with Weinreb amides, ketones, or carbonates to provide the corresponding carbonyl derivatives after acidic cleavage. This allows for an efficient synthesis of 1,2‐dicarbonyl compounds and α‐hydroxy ketones.
Reduction of Weinreb amides to aldehydes under ambient conditions with magnesium borohydride reagents
作者:Christopher L. Bailey、Jacob W. Clary、Chittreeya Tansakul、Lucas Klabunde、Christopher L. Anderson、Alexander Y. Joh、Alexander T. Lill、Natalie Peer、Rebecca Braslau、Bakthan Singaram
DOI:10.1016/j.tetlet.2014.12.066
日期:2015.1
[H3BNMe2]−, MgAB) is an analogue of the versatile lithium dialkylaminoborohydrides (LAB reagents), prepared by the reaction of dimethylamine-borane with methylmagnesium chloride. MgAB is a partial reducing agent for Weinrebamides under ambient conditions and is complementary to the commonly utilized lithium aluminum hydride (LiAlH4) and diisobutylaluminum hydride (DIBAL) reagents, while exhibiting enhanced
One-Pot Transition-Metal-Free Synthesis of Weinreb Amides Directly from Carboxylic Acids
作者:Danfeng Huang、Yulai Hu、Teng Niu、Ke-Hu Wang、Changming Xu、Yingpeng Su、Ying Fu
DOI:10.1055/s-0033-1340317
日期:——
directly fromcarboxylicacids, N,O-dimethylhydroxylamine, and phosphorus trichloride in one pot at 60 °C in toluene in high yields, thus avoiding the separation of the moisture and air sensitive intermediate P[NMe(OMe)]3 in advance. Sterically hindered carboxylicacids also give the corresponding Weinreb amides in excellent yields. Various functional groups are tolerated on the carboxylicacid. The method
of iminyl radical‐triggered 1,5‐hydrogen atom transfer and (5+2) or (5+1) annulation processes, a series of structurally novel and interesting azepine and spiro‐tetrahydropyridine derivatives have been successfully prepared in moderate to good yields. This method utilizes FeCl2 as the catalyst and readily available oximes as five‐atom units, while showcasing broad substrate scope and good functional