Due to an unexpectedly difficult reduction of indole-3-carbaldehyde and of isobutyraldehyde using the chiral reducing agent Alpine-Borane, the reactivity of several aliphatic, aromatic, and unsaturated aldehydes was investigated. This was done in order to determine whether there was a relationship between aldehyde structure and reduction rate. It was found that aliphatic aldehydes and aromatic aldehydes with no strongly electron-donating groups on the arene ring reduced faster than unsaturated aldehydes.
Bland, Layla and Panigot, Michael J.
"Reaction of Alpine-Borane with Aldehydes: Reactivity Rate Assessment by Observation of the Disappearance of the Carbonyl n - Pi* Peak by UV-Visible Spectroscopy,"
Journal of the Arkansas Academy of Science: Vol. 54
, Article 6.
Available at: http://scholarworks.uark.edu/jaas/vol54/iss1/6