Efficient Synthesis of α-Aryl Esters by Room-Temperature Palladium-Catalyzed Coupling of Aryl Halides with Ester Enolates
作者:Morten Jørgensen、Sunwoo Lee、Xiaoxiang Liu、Joanna P. Wolkowski、John F. Hartwig
DOI:10.1021/ja027643u
日期:2002.10.1
arylation of alpha,alpha-disubstituted esters were developed with LiNCy(2) as base and P(t-Bu)(3) as ligand. In addition, tert-butyl esters, such as those of Naproxen and Flurbiprofen, were prepared from tert-butyl propionate and aryl bromides in high yields in the presence of Pd(dba)(2) and the hindered, saturatedheterocycliccarbene ligand precursor.
Regioselective Arene C−H Alkylation Enabled by Organic Photoredox Catalysis
作者:Natalie Holmberg‐Douglas、Nicholas P. R. Onuska、David A. Nicewicz
DOI:10.1002/anie.202000684
日期:2020.5.4
metallocarbene species, which is capable of direct insertion into an aromatic C-H bond. However, these high-energy intermediates can often require directing groups or a large excess of substrate to achieve efficient and selective reactivity. Herein, we report that arene cation radicals generated by organic photoredox catalysis engage in formal C-H functionalization reactions with diazoacetate derivatives, furnishing
Iron-catalyzed Chemoselective Cross-coupling of α-Bromocarboxylic Acid Derivatives with Aryl Grignard Reagents
作者:Masayoshi Jin、Masaharu Nakamura
DOI:10.1246/cl.2011.1012
日期:2011.9.5
We have developed a simple and effective synthetic method of α-arylcarboxylic acid derivatives based on the iron-catalyzed cross-coupling reaction of α-bromocarboxylic acid derivatives with aryl Grignard reagents. The reaction proceeds smoothly at −78 °C in a chemoselective manner to produce the coupling product in good to excellent yields.
Palladium-Catalyzed α-Arylation of Esters and Protected Amino Acids
作者:Sunwoo Lee、Neil A. Beare、John F. Hartwig
DOI:10.1021/ja016032j
日期:2001.8.1
One-step deprotonation route to zinc amide and ester enolates for use in aldol reactions and Negishi couplings
作者:Mark L. Hlavinka、John R. Hagadorn
DOI:10.1016/j.tetlet.2006.05.093
日期:2006.7
Simple amides and esters are conveniently deprotonated by Zn(tmp)(2) (tmp = 2,2,6,6-tetramethylpiperidinyl anion) to generate Zn enolates. Enolates formed by this method are suitable for use in aldol reactions that tolerate base-sensitive functional groups. Additionally, the Zn enolates are readily coupled with aryl bromides using typical Pd-catalyzed coupling methods. (c) 2006 Elsevier Ltd. All rights reserved.