The α,α-Dihalocarbonyl Building Blocks: An Avenue for New Reaction Development in Organic Synthesis.

The α,α-dihalocarbonyl moiety is a bifunctional system with a gem-dihalocarbon and a carbonyl carbon in 1,2-fashion. This is one of the privileged scaffolds in medicinal chemistry due to its chemical and metabolic stability and lipophilicity. They have also been found in numerous structurally divergent natural products and most of their fabricated structures have already been in medicinal use. Apart from their important use in medicinal chemistry, the α,α-dihalocarbonyl groups have been employed as key building blocks for the development of novel synthetic strategies and utilized as intermediates in total synthesis. In addition to the traditional transformations such as oxidations, reductions, and C-C bond formations, recently several new and non-classical reactions have also been developed. This review provides short description of existing methods for their synthesis and detailed discussion on the efforts for the discovery and development of new reactions by employing α,α-dihaloketones as synthetic building blocks. We have presented their use as key functional groups for the synthesis of polycyclic systems of medicinal and material importance and natural products.