Applying the Principles of Green Chemistry to Cyclopropanation

The cyclopropane motif is widely found in many natural products and drug candidates with relevant biological activities. Moreover, due to their strained ring, cyclopropanes possess higher reactivity compared to other alkanes, giving access to a wide range of transformations. Therefore, the preparation of cyclopropanes has attracted much attention over the past decades. However, the increased awareness of the environmental impact of industries and laboratories has sparked the interest in the synthesis of cyclopropanes using the principles of green chemistry. The aim of this review is to give an overview of the cyclopropanation strategies that take into consideration the principles of Green Chemistry. The calculation of the E-factor of a selection of the presented examples provides further insights into the importance of evaluating a chemical process through to the isolated pure product.