Highly efficient and environmentally benign preparation of Weinreb amides in the biphasic system 2-MeTHF/water
作者:Vittorio Pace、Laura Castoldi、Andrés R. Alcántara、Wolfgang Holzer
DOI:10.1039/c3ra41262h
日期:——
A straightforward chromatography-free preparation of Weinreb amides starting from acid halides has been achieved in the biphasic medium 2-MeTHF/water. Analytically pure compounds were isolated in excellent yields simply after removal of 2-MeTHF, which absolutely avoids the use of any contaminant organic solvent within the whole process due to its (practically) immiscibility with water.
α-Effect with Substituted <i>N</i>-Methylbenzohydroxamates and Substituted Phenyldimethylsulfonium Salts: Toward Understanding of an Intrinsic α-Effect
作者:K. R. Fountain、Timothy W. Dunkin、Kamlesh D. Patel
DOI:10.1021/jo9620021
日期:1997.5.1
ium ions decreases the alpha-effect for the methyl transfers toward 1.0 (zero effect). An extrapolation shows the possibility of an inverse effect (<1.0). The reactivity of G-NMBH anions correlates with SET parameters and with the known propensity of phenyldimethylsulfonium ions to accept a single electron into a sigma C-S orbital concomitant with expulsion of a CH(3) group. These correlations indicate
A Powerful Reagent for Synthesis of Weinreb Amides Directly from Carboxylic Acids
作者:Teng Niu、Weiming Zhang、Danfeng Huang、Changming Xu、Haifeng Wang、Yulai Hu
DOI:10.1021/ol901886u
日期:2009.10.1
A powerful reagent, P[NCH3(OCH3)](3) (3), for conversion of carboxylic acids directly to Weinreb amides was developed. In most cases the yields of the corresponding Weinreb amides were above 90% when P[NCH3(OCH3)13 was heated with aromatic and aliphatic carboxylic acids in toluene. The sterically hindered carboxylic acids can also give the corresponding Weinreb amides in excellent yields.
Fountain, Kenneth R.; Fountain, Daniel P.; Michaels, Bernice, Canadian Journal of Chemistry, 1991, vol. 69, # 5, p. 798 - 810
作者:Fountain, Kenneth R.、Fountain, Daniel P.、Michaels, Bernice、Myers, D. Brenton、Salmon, Jon K.、et al.
DOI:——
日期:——
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