Ak. Lala et Ap. Gokhale, INTRAMOLECULAR REMOTE FUNCTIONALIZATION OF STEROIDS BY BENZOPHENONE -INCREASED SPECIFICITY BY SOLVENT-INDUCED HYDROPHOBIC INTERACTIONS, Proceedings of the Indian Academy of Sciences. Chemical sciences, 106(5), 1994, pp. 971-981
Proximity of reactant sites is one of the major factors that contribut
es to specificity and high reaction rates observed in enzyme catalysis
. Enzymes achieve this proximity between the reactant sites by having
high affinity for the substrate. Structural studies on enzyme-substrat
e complexes provide sufficient evidence in this context and indicate t
hat weak bonding interaction are involved in formation of such complex
es. We have exploited the hydrophobic interaction between cholesterol
and benzophenone to carry out photoinduced remote functionalisation of
cholesterol at specific sites. Thus, using polar solvents intramolecu
lar hydrophobic interaction between cholesterol and benzophenone permi
tted exclusive functionalisation of ring D in cholesterol. The current
study indicates that weak interactions between the reactants can be u
sed to bring them in proximity and photochemical reactions can provide
the method for functionalising even inert sites like C-H bonds.