Progress in studies on the RNA world.

The montmorillonite-catalyzed reactions of D, L-ImpA with D, L-ImpU generates RNA-like oligomers. The structures of the dimers to pentamers were investigated and homochiral products were identified in greater amounts than would be expected if theoretical amounts of each were formed. The homochirality increased from 64% to 97% as the chain length increased from dimers to pentamers. Investigation of the effect of pH, occupancy of the interlayer space and the influence of various cations in the reaction provided further insight into physical process in the mechanism of the catalysis. A detailed analysis of dimers was carried out in view of there being key intermediates towards formation of higher oligomers. The study was extended to the synthesis of non-standard dimers including those formed with deoxy-ribonucleotides.