One Pot, Two Phases: Iron-Catalyzed Cyclopropanation with In Situ Generated Diazomethane

摘要

Cyclopropyl units have proven to be important structural elements in organic chemistry. They occur in numerous natural products and active substances including terpenes, fatty acids, and unusual nonproteinogenic amino acids. Cyclopropyl residues are frequently used in medicinal chemistry to fix the stereochemistry of substituents or to provide the middle ground between the space requirement of a methyl and an isopropyl moiety. Being flexible in their reactivity, cyclopropanes serve as versatile building blocks for the synthesis of a variety of heterocyclic frameworks. Both the ring strain and the distinct "double-bond character" of the three-membered ring play a crucial role in the reactivity of cyclopropane rings.