The synthesis of homoallylic alcohols through diasteriomeric transition states

Theoretically, optically active homoallylic alcohols can be synthesized by reacting an optically active organotin with an aldehyde in the presence of a Lewis acid. It is expected that the chirality of the organotin will induce one diastereomeric transition state which will have a significantly reduced activation energy than the transition state of the other diastereomer. If the difference between the two activation energies is substantial enough, the transition state with the lower activation energy will be preferred over the other transition state. If the preference is absolute one completely pure alcohol enantiomer will be produced. If there is a preference, but it is not absolute, there will be an excess of one enantiomer produced. Various aldehydes were reacted with the synthesized organotin, diallylisopropylmyrtanyltin to produce alcohols. Three aldehydes (benzaldehyde, ortho -chlorobenzaldehyde, and 2-ethylhexanal) were used to determine the correlation, if any, between the optical purity of the reaction product and the reacting aldehyde. The optical rotations measured for each of the alcohols produced revealed no correlation: the products were racemic mixtures, regardless of the aldehyde used