Abstract:
The potential of substituted hydrofluorenones for syntheses of biological and related products has been reviewed.
General syntheses of substituted hexahydrofluoren-9-ones from benzoic acids and cyclohexanols or their esters have been realised using 91% polyphosphoric acid.
Alternative reagents using phosphorus pentoxidemethanesulphonic acid, and trifluoroacetic anhydride have been developed.
A modified Pictet Spengler reaction suitable for the synthesis of morphinan has been discovered.
The introduction of functionality into the C4a position of hydrofluoren-9-ones; and a study of a base induced debromination of a 9a-bromo-4a-methyl-hydrofluoren-9-one have been investigated.
1H, and 13C n.m.r. methods have been used to clarify structural features of hydrofluoren-9-ones.
Iodolactonisation of unsaturated acids catalysed by thallous, sodium and ammonium acetates, and iodine have been investigated. It has been found that the use of thallous acetate allows the products of kinetic control to be obtained. A rationale to account for the different abilities of the thallous and sodium salts to stabilise iodo-β-lactones has been proposed.
Iodolactonisation of an unsaturated ester has been achieved.