Stephen Charles Case-Green

Analysing genetic information with DNA arrays.

The large amount of DNA sequence information produced in recent years has created a need for high-throughput methods in biology and genetics. These include sequencing, comparing gene sequences and genotyping. DNA arrays promise a highly parallel means for analysis of DNA that is fast and cost-effective, and offers scope for application to complex systems and processes. Recent years have seen continued transfer of technology from the microelectronics industry. Rapid application of the technology to genotyping, antisense oligonucleotide selection and gene expression analysis has illustrated the general power of this approach.

Kinetic resolution of the chiral iron acetyl complexes [Fe(CO)(η5-C5H5)(L)COCH3][L = PPh3, P(p-tolyl)3]via aldol reactions with camphor

The chiral iron acetyl complexes [Fe(CO)(η5-C5H5)(L)COCH3][L = PPh3, P(p-tolyl)3] have been kinetically resolved via aldol reactions involving their derived lithium enolates and camphor in the presence of lithium chloride. With (1R)-(+)-camphor the faster reacting iron acetyl enantiomer had the (S)-configuration allowing the (R)-iron acetyls to be obtained after recovery of starting material and crystallisation. The corresponding (S)-iron acetyls can be obtained by a base-promoted reverse aldol reaction of the isolated products. A mechanistic rationale for the high enantiomeric discrimination is proposed which involves a chelation-controlled chair transition state with a disfavourable 1-methyl to cyclopentadienyl interaction in the mismatched pairing.

Kinetic resolution of the chiral iron acetyl [Fe(η5-C5H5)(CO)(PPh3)COMe]

The chiral discrimination displayed between the enolate derived from (RS)-[Fe(η5-C5H5)(CO)(PPh3)COMe] and (1R)-(+)-camphor furnishes a practical route to homochiral (R)-[Fe(η5-C5H5)(CO)(PPh3)COMe]via a kinetic resolution protocol, while a retro-aldol reaction of the diastereoisomerically pure aldol addition product of this kinetic resolution sequence provides a complementary route to the opposite enantiomer (S)-[Fe(η5-C5H5)(CO)(PPh3)COMe].