A Diazo-Hooker Reaction, Inspired by the Biosynthesis of Azamerone

Recent advances in 8π electrocyclization reactions

Medium-ring systems, which constitute a class of structurally intriguing and biologically important molecules, are present in many natural products and pharmaceuticals. However, the construction of these skeletons tends to be difficult because of the torsional strain of the medium-sized ring, and control of the selectivity is also challenging in these flexible skeletons. Electrocyclization is one of the most straightforward methods to construct medium-sized rings and this process typically proceeds in a stereospecific manner, resulting in the stereo-controlled formation of two neighboring stereocenters. At present, there are few studies on 8π electrocyclization, mainly focusing on the synthesis of small molecules, while the applications in the synthesis of functional materials and biological contexts are rare. This feature article highlights recent advances, from 2000 to 2022, in the 8π electrocyclization reaction. This study is organized into four sections based on the size/composition of the target ring, including the synthesis of aza-seven-membered, cycloheptene, cyclooctene and bicyclo[4,2,0]octane frameworks. We expect that this feature article will provide beneficial guidance for the selective construction of medium-ring skeletons.

The seven-step, one-pot regioselective synthesis of biologically important 3-aryllawsones: scope and applications

3-Aryllawsones are well known for their wide range of applications in medicinal chemistry, but their synthesis has always remained challenging as no comprehensive protocol has been outlined to date. Owing to their structural importance, we synthesized various 3-aryllawsones with high regioselectivity from simple lawsone and aldehydes in a seven-step double-cascade one-pot reaction through the combination of organocatalytic Ramachary reductive coupling and Hooker oxidation reactions. The commercial availability of the starting materials, diverse substrate scope, possibility of a one- or two-pot approach, regioselectivity of alkyl transfer (with mechanistic proof provided via X-ray crystal structure analysis), and numerous medicinal applications of 3-aryllawsones are the key attractions of this work.