Modern Cyclopropanation via Non‐Traditional Building Blocks

Small, strained carbocyclic systems have fascinated organic chemists from both a theoretical and synthetic standpoint. These systems often challenge conventional wisdom when it comes to molecular structure and tactics for chemical construction. The cyclopropyl motif is one such ring system that remains at the forefront of method development in the modern era. With the advent of an array of non-traditional building blocks, a range of new cyclopropanation processes using one- and two-electron strategies have been developed that not only overcome the synthetic shortcomings of classical approaches but also provide entry into a wide range of new classes of cyclopropanes. This review discusses recent advances in this area with an emphasis on their mechanistic underpinnings and potential applications. Additionally, a concise overview of the properties of and traditional approaches to cyclopropanes is provided.