Some Aspects of Reductive Amination in the Presence of Carbon Monoxide: Cyclopropyl Ketones as Bifunctional Electrophiles

Abstract

We conducted detailed studies on CO-assisted reductive chemistry with cyclopropyl ketones as a special type of substrate. Multiple factors influencing the outcome of the reaction have been studied for both ruthenium and rhodium catalysis. An unusual rearrangement of aminomethylcyclopropanes was found. We showed that some reductive reactions, which were believed to proceed through a water–gas shift reaction pathway, can nonetheless take place even without an external or internal water source, indicating a more interesting reaction mechanism. Cyclopropylketones were employed as bifunctional electrophiles and, depending on the conditions, the reaction with an amine can lead to a number of products, including aminoketones, cyclopropyl methylamines, pyrrolidines or 1,4-diaminopentanes.