Theoretical elucidation of kinetic and thermodynamic control of radical addition regioselectivity.

نویسندگان

  • Andrew G Leach
  • Renxiao Wang
  • G Erich Wohlhieter
  • Saeed I Khan
  • Michael E Jung
  • K N Houk
چکیده

The cyclizations of two structurally similar 2-oxo-5-hexenyl-type radicals have been investigated by ab initio and density functional (UB3LYP/6-31+G**//UHF/6-31G* and UB3LYP/6-31G*//UB3LYP/6-31G*) calculations. The origin of apparently contradictory reports of 6-endo and 5-exo cyclizations is determined. Kinetic control favors 6-endo cyclization, while thermodynamic control gives 5-exo cyclization, and the observation of different products from different research groups arises from the difference in experimental conditions used by the two groups. The outcome of a new cyclization reaction was predicted by using these theoretical techniques. Kinetic control is predicted to yield exclusively the products of 6-endo cyclization, while thermodynamic control would lead to an approximately equal mixture of one 6-endo and one 5-exo cyclized product. Experimental studies revealed that the reaction yields only the products of 6-endo cyclization through kinetic control.

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عنوان ژورنال:
  • Journal of the American Chemical Society

دوره 125 14  شماره 

صفحات  -

تاریخ انتشار 2003