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Halophilic attack on carbon-halogen bond by nucleophiles has recently become a sub-ject of interest and intensive study.A wide variety of substrates and nucleophiles has beenexamined.But no quantitative measurements on the reactivities of substrates have ever beenreported.The present work is a first attempt to evaluate the relative reactivities of perfluoro-bromoalkanes(R-Br)and some bromo organic compounds(R-Br)by intermolecular compe-tition kinetics.A large excess of Cl_3CCF_2CF_2Cl(1),a chlorine-containing substrate withconvenient reactivity toward halophilic attack,and R-Br is used to compete for a small amountof the enolate anion of mesityl isopropyl ketone(E-)in dimethyl formamide(DMF)at 20℃in their reactions to form α-chloroisopropyl mesityl ketone(A)and α-bromoisopropylmesityl ketone(B)as products(eq 1)
Halophilic attack on carbon-halogen bond by nucleophiles has recently become a sub-ject of interest and intensive study. A wide variety of substrates and nucleophiles have benexnexined. On no reactivity of substrates have ever been reported. The present work is a first attempt to evaluate the relative reactivities of perfluoro-bromoalkanes (R-Br) and some bromo organic compounds (R-Br) by intermolecular compe- tition kinetics. A large excess of Cl_3CCF_2CF_2Cl (1), a chlorine-containing substrate with unconvenient reactivity toward halophilic attack, and R-Br is used to compete for a small amount of the enolate anion of mesityl isopropyl ketone (E-) in dimethyl formamide (DMF) at 20 ° C in their reactions to form α-chloroisopropyl mesityl ketone (A) and α -bromoisopropylmesityl ketone (B) as products (eq 1)