Enthalpy versus entropy in chlorocarbene/alkene addition reactions.
We report the first measured activation parameters for the additions of CCl2 and CClF to simple alkenes and demonstrate the existence of enthalpic barriers for CCl2 additions to cyclohexene and 1-hexene. With these two alkenes, additions of PhCCl are "dominated" by entropic contributions to deltaG++ and additions of CCl2 display comparable contributions of deltaH++ and deltaS++, while CClF additions feature dominant enthalpic contributions to deltaG++. Entropic factors, however, control the additions of all three carbenes to the highly reactive alkene, tetramethylethylene. Parallel computational studies are also reported.
Moss
Robert A
RA
Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, USA. moss@rutchem.rutgers.edu
Wang
Lei
L
Zhang
Min
M
Skalit
Christopher
C
Krogh-Jespersen
Karsten
K