Kabbe condensation: a comprehensive review of spirochromanone synthesis and medicinal applications

The Kabbe reaction is an organic condensation reaction that specifically involves an enamine and 2-hydroxy acetophenone reacting to form a spirochromanone skeleton. This review covers various methods and advancements, highlighting a range of Kabbe products, particularly spirochromanones, which are heterocycles exhibiting significant biological activities. The Kabbe method incorporates ring-closing metathesis (RCM), the synthesis of annulated chalcone conjugates, natural product synthesis, base-catalyzed reactions, organo-catalysis, Mukaiyama-Kabbe adaptations, organocatalytic variants, redox-mediated processes, and dual or sequential condensations. Consequently, researchers in this domain will find this overview valuable and beneficial towards the synthesis of various Kabbe products in the synthesis of spirochromanones, spirochromanone-chalcone hybrids, carbamide molecular hybrids, and spirochromanone-flavanone hybrids. This review provides a comprehensive overview of spirochromanones and their derivatives, covering literature from their inception up to 2025.