Photodimerisation of enones in a clay microenvironment.
The photodimerisation of 2-cyclohexenone, 2-cyclopentenone and their 3-methyl derivatives is studied in the confined environment of clay interlayers. In the photolysis of 2-cyclohexenone, a remarkable regioselectivity is observed in favour of the head-to-head dimer when carried out in cation-exchanged bentonite clays while the dimerisation of 2-cyclopentenone favours the formation of the head-to-tail dimer. The results are explained on the basis of the ground state pre-organisation of enones and also the complexing ability of charge-balancing cations with the carbonyl oxygen of enone. In addition to the observed regioselectivity, other advantages of employing clays in photochemical studies are highlighted.
Madhavan
Durairajan
D
School of Chemistry, Madurai Kamaraj University, Madurai 625 021, India.
Pitchumani
Kasi
K