Investigation of Aminonitriles as Organocatalysts.

This project built upon previous work with amino acid derivatives in the Clarke group. Originally, L-valine nitrile 4 and L-proline nitrile 5 were investigated for the first time as catalysts for the aldol reaction of 4-nitrobenzaldehyde 1 and cyclohexanone 2 in an array of organic solvents. Interestingly, a new proline derivative 6 was synthesised and also investigated for the first time.

Aminonitrile 4 afforded the aldol adducts with an interesting major syn diastereomer but the results in terms of conversion and enantioselectivity were discouraging. Aminonitrile 5 showed a better catalytic efficiency than 4 in terms of conversion, however, the enantioselectivity was moderate. Proline imidate 6 was investigated as an organocatalyst for the first time and promising results were gained. L-Proline imidate 6 was trialled in an array of organic solvents and different aldehydes and 6 afforded the anti (major) aldol diastereomer in a good enantiomeric excess with up to 94% ee.