One-pot synthesis of Weinreb amides employing 3,3-dichloro-1,2-diphenylcyclopropene (CPI-Cl) as a chlorinating agent
作者:Shekharappa M、Roopesh Kumar L、Vommina V. Sureshbabu
DOI:10.1080/00397911.2018.1531295
日期:2019.3.19
Abstract The synthesis of Nα-protected amino alkyl Weinrebamides starting from the corresponding α-amino acids as well as carboxylic acids has been delineated through the in situ generation of acid chlorides using CPI-Cl as a chlorinating agent. The protocol is simple; the reaction conditions employed were mild, and compatible with all the three commonly used urethane protecting groups namely, Boc
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
Carbamoylimidazolium and thiocarbamoylimidazolium salts: novel reagents for the synthesis of ureas, thioureas, carbamates, thiocarbamates and amides
作者:Justyna A. Grzyb、Ming Shen、Chiaki Yoshina-Ishii、W. Chi、R.Stanley Brown、Robert A. Batey
DOI:10.1016/j.tet.2005.05.056
日期:2005.7
Carbamoylimidazolium salts act as efficient N,N-disubstituted carbamoylating reagents. These salts are readily prepared by the sequential treatment of secondary amines with N,N′-carbonyldiimidazole (CDI) and iodomethane. The carbamoylimidazolium salts are more efficient carbamoyl transfer reagents than the intermediate carbamoylimidazoles, as a result of the ‘imidazolium’ effect. Kinetic studies on
Synthesis of Difluoromethyl Ketones from Weinreb Amides, and Tandem Addition/Cyclization of <i>o</i>
-Alkynylaryl Weinreb Amides
作者:Jongkonporn Phetcharawetch、Nolan M. Betterley、Darunee Soorukram、Manat Pohmakotr、Vichai Reutrakul、Chutima Kuhakarn
DOI:10.1002/ejoc.201701322
日期:2017.12.15
[Difluoro(phenylsulfanyl)methyl]trimethylsilane (PhSCF2SiMe3) underwent a fluoride-induced nucleophilic addition to the carbonyl group of Weinreb amides to provide the corresponding difluoro(phenylsulfanyl)methyl ketones. These were converted into difluoromethyl ketones through selective reductive cleavage of the phenylsulfanyl group. The reaction of o-alkynyl Weinreb amides derived from benzoic acid derivatives resulted
Palladium-Catalyzed, <i>ortho</i>-Selective C–H Halogenation of Benzyl Nitriles, Aryl Weinreb Amides, and Anilides
作者:Riki Das、Manmohan Kapur
DOI:10.1021/acs.joc.6b02731
日期:2017.1.20
ortho-selective C–H halogenation methodology is reported herein. The highlight of the work is the highly selective C(sp2)–H functionalization of benzyl nitriles in the presence of activated C(sp3)–H bond, which results in good yields of the halogenated products with excellent regioselectivity. Along with benzyl nitriles, aryl Weinrebamides and anilides have been evaluated for the transformation using aprotic