Related Experiment Video
Updated: May 12, 2026

Preparation of N-(2-alkoxyvinyl)sulfonamides from N-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines
Published on: January 3, 2018
Conjugate addition of diethyl 1-fluoro-1-phenylsulfonylmethanephosphonate to α,β-unsaturated compounds
Stanislav Opekar1, Radek Pohl, Václav Eigner
1Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Prague, Czech Republic.
Abstract:
Diethyl 1-fluoro-1-phenylsulfonylmethanephosphonate (1) in the presence of cesium carbonate undergoes efficient 1,4-addition to Michael acceptors having terminal double bonds such as α,β-unsaturated ketones, esters, sulfones, sulfoxides, and phosphonates to yield the corresponding adducts in good to excellent yields. In the presence of sodium hydride, 1 reacts with α,β-enones to provide γ-fluoro-γ-phenylsulfonylenol phosphates arising from 1,4-addition followed by phosphonate to phosphate rearrangement.
Related Concept Videos
Conjugate Addition to α,β-Unsaturated Carbonyl Compounds
Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)
Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon.
Direct addition products are formed faster owing to...
Conjugate Addition of Enolates: Michael Addition
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Preparation and Reactions of Sulfides
