The One-Pot Wittig Reaction: A Facile Synthesis of α,β-Unsaturated Esters and Nitriles by Using Nanocrystalline Magnesium Oxide
作者:Boyapati M. Choudary、Koosam Mahendar、M. Lakshmi Kantam、Kalluri V. S. Ranganath、Taimur Athar
DOI:10.1002/adsc.200606001
日期:2006.9
Nanocrystalline magnesium oxide was found to be an effective heterogeneous, solid base catalyst for the one-pot Wittig reaction to afford α,β-unsaturatedesters and nitriles in excellent yields with high E-stereoselectivity in the presence of triphenylphosphine under mild conditions.
A Facile and Mild Approach for Stereoselective Synthesis of α-Fluoro-α,β-unsaturated Esters from α-Fluoro-β-keto Esters via Deacylation
作者:Wenbin Yi、Jinlong Qian、Meifang Lv、Chun Cai
DOI:10.1055/s-0034-1378917
日期:——
The highly stereoselective olefination reaction of α-fluoro-β-keto esters for the synthesis of α-fluoro-α,β-unsaturated esters has been developed. The olefination combines nucleophilic addition, intramolecular nucleophilic addition, and elimination in one step, as well as provides a facile synthetic approach to α-fluoro-α,β-unsaturated esters which are important units in many biologically active compounds
The Z-selective formation of α-fluoro-α,β-unsaturated esters was achieved using the deselenenic acid of the syn- and/or anti-3-aryl-2-fluoro-3-hydroxy-2-organoselanylacetates 3 and 4 with trifluoro...
Grignard and organolithium reagents efficiently react with (S)-N-(tert-butanesulfinyl)-α-fluoroenimines to provide chiral allylamines in excellent yields and with diastereomeric ratios of up to 96:4. Acidic removal of the sulfinyl group and simple functional group transformations allow to get enantiopure fluoroolefin dipeptide mimics.
The synthesis of α-fluoroacrylates and α-bromo-α-fluoroalkenes was achieved in very good yields using aldehydes and ketones, triphenylphosphine, diethylzinc as promoter, and ethyl dibromofluoroacetate or dibromofluoromethane, respectively. A change in the addition sequence was critical in order to obtain exclusively α-fluoroacrylates in good yields.