Recent developments of α-nitroketones/α‑nitro-α,β-unsaturated ketones as nucleophilic/electrophilic acyl transfer reagents in the catalytic asymmetric reaction
摘要
The utilization of α-nitro ketones and α-nitro-α,β-unsaturated ketones as both nucleophilic and electrophilic acyl transfer agents has attracted significant attention in asymmetric synthesis due to their unique electronic characteristics and high reactivity. The presence of the strongly electron-withdrawing nitro group at the α-position significantly enhances the acidity of adjacent protons and activates the carbonyl group of α-nitro ketones toward nucleophilic attack. A comparable activation effect is observed in α-nitro-α,β-unsaturated ketones where the conjugated olefinic moiety becomes more susceptible to nucleophilic addition. This dual reactivity enables a wide range of asymmetric acyl transfer processes under mild and enantioselective conditions. In asymmetric catalysis, these nitro-substituted ketones serve as versatile intermediates capable of generating chiral acylated products with excellent enantiocontrol and also demonstrate their efficiency in enantioselective carbon–carbon and carbon-hetero bond-forming reactions to access highly functionalized chiral building blocks. The development of these reagents provides an environmentally benign alternative to traditional acyl reagents by minimizing corrosive by-products and improving atom economy. Moreover, the nitro group can be readily transformed into various functional motifs, broadening the synthetic utility of these compounds. This review highlights recent developments in the use of α-nitroketones and α-nitro-α,β-unsaturated ketones as bifunctional acyl transfer reagents, focusing on mechanistic insights, catalyst design, and their applications in the construction of optically active building blocks relevant to pharmaceutical and natural product chemistry.