Copper-catalyzed and promoted difunctionalization reactions of unactivated alkenes: Aminooxygenation, diamination, carboetherification and dioxygenation
Karyakarte, Shuklendu Dilip
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Alkene difunctionalization has emerged as an attractive method for the construction of complex functionalized molecules. One of the frontiers vastly explored in this area of research is the synthesis of five-, six- and seven-membered heterocyclic rings via the cyclization strategy. The research presented here attempts to further the utility of copper(II)-mediated alkene difunctionalization strategies towards the synthesis of a diverse class of such heterocycles. In chapter one, a copper(II)-catalyzed stereoselective synthesis of five-membered isoxazolidines is reported. This method cyclizes a range of N -sulfonyl- O -butenyl hydroxylamines efficiently in good yields and diastereoselectivities. The products are also functionalized to form γ-lactones and substituted 3-amino-1,4-diols, which have a high utility in synthetic chemistry. Chapter two includes my contribution towards the kinetic studies carried out for the copper(II)-catalyzed enantioselective aminooxygenation of alkenes, wherein I determined the thermodynamic parameters of this reaction. In chapter three, we have expanded the utility of copper(II)-promoted intra/intermolecular diamination strategy towards the synthesis of seven-membered 1,4-benzodiazepinones, which is an ubiquitous core in medicinal chemistry. Finally in chapter four, the first copper(II)-catalyzed enantioselective synthesis of spiroethers from 1,1-disubstituted alkenols is reported. Spirocycles in general and spiroethers in particular are structurally complex molecules. The reported method employs a doubly intramolecular carboetherification strategy to access these scaffolds in high yields and excellent enantioselectivities. A doubly intramolecular dioxygenation of alkene-diols has also been explored in this study.