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A Hetero Retro Diels–Alder Reaction in Aqueous Solution: A Dramatic Water‐Induced Increase of the Equilibrium Constant and Inhibition of Cycloreversion
Author(s) -
Wijnen Jan W.,
Engberts Jan B. F. N.
Publication year - 1997
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199719970607
Subject(s) - nitrosobenzene , chemistry , adduct , aqueous solution , reaction rate constant , cyclopentadiene , equilibrium constant , photochemistry , diels–alder reaction , computational chemistry , organic chemistry , catalysis , kinetics , physics , quantum mechanics
The adduct of the Diels–Alder reaction of nitrosobenzene with cyclopentadiene is not stable in solution. The equilibrium constant for the reaction depends strongly on the medium and water induces a spectacular shift to the adduct. Comparison with the bimolecular addition of nitrosobenzene to 1,3‐cyclohexadiene enables separation of the effect of the aqueous medium on the rate constants for the forward and reverse reaction. In water, the former reaction is accelerated and the latter is retarded. The deceleration of the retro reaction in water is due to hydrogen‐bond stabilization of the adduct. The influence of cosolvents and micelles on the cycloreversion is discussed.