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Nucleophilic Fluoroalkylation of α , β ‐Unsaturated Carbonyl Compounds with α ‐Fluorinated Sulfones: Investigation of the Reversibility of 1,2‐Additions and the Formation of 1,4‐Adducts
Author(s) -
Shen Xiao,
Ni Chuanfa,
Hu Jinbo
Publication year - 2012
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201200445
Subject(s) - chemistry , adduct , isomerization , nucleophile , medicinal chemistry , ion , nucleophilic addition , organic chemistry , catalysis
Abstract A detailed investigation of the reactions of PhSO 2 CF 2 H and PhSO 2 CH 2 F with ( E )‐chalcone (=( E )‐1,3‐diphenylprop‐2‐en‐1‐one) at low temperatures revealed that these two reactions were kinetically controlled, and the ratios of 1,2‐ vs. 1,4‐adducts, which did not change much over time at these temperatures, reflect the relative rates of the two reaction pathways. The controlled experiments of converting the PhSO 2 CF 2 ‐ and PhSO 2 CHF‐substituted 1,2‐adducts to 1,4‐adducts showed that these isomerizations are not favored due to the low stability and hard‐soft nature of PhSO 2 CF $\rm{{_{2}^{-}}}$ and PhSO 2 CHF − anions. Moreover, taking advantage of the remarkable stability and softness of (PhSO 2 ) 2 CF − anion, an efficient thermodynamically controlled isomerization of (PhSO 2 ) 2 CF‐substituted 1,2‐adduct to 1,4‐adduct was achieved for the first time.