The Nazarov cyclization is one of the most efficient synthetic approaches for the synthesis of five-membered carbocycles, utilizing the 4π-conrotatory electro-cyclization. However, in recent years, alternative methodologies that significantly enhance the practicality of this reaction have emerged. The hetero and homo-Nazarov cyclization, which incorporates nitrogen, oxygen, and cyclopropyl group into the divinyl ketone skeleton, facilitates the synthesis of hetero cycles and cyclohexanones.

Abstract

The Nazarov cyclization of divinyl ketones is one of the most efficient synthetic approaches for the formation of five-membered carbocycles, utilizing the 4π-conrotatory electro-cyclization of a conjugated penta-dienyl cation. However, in recent years, alternative methodologies that significantly enhance the practicality of this reaction have emerged. Motivated by these developments, the scientific community has broadened the applicability of original reactions to a wide array of starting materials. The hetero Nazarov cyclization, which incorporates nitrogen and oxygen into the divinyl ketone skeleton, facilitates the synthesis of hetero cycles, whereas the substitution of the cyclopropyl group with one of the vinyl moieties yields cyclohexanones through homo Nazarov cyclization. These Nazarov-like cyclizations are the theme of this review and introduce an overview of recent advances in hetero- and homo-Nazarov cyclizations, categorizing this reaction according to the structure of the modified divinyl ketone. Our aim is to accelerate the progress in this rapidly evolving field of research.