Novel Synthetic Routes to Functionalized Tetrahydrobenzofurans and Chiral a-Quaternary a\u27-Hydroxy Ketones

Various naturally occurring organic compounds possess unique biological activities and have found exclusive applications in pharmaceuticals and agrochemicals. Their undeniable significance has necessitated the discovery and development of novel reactions that unveil advanced chemical transformations. This dissertation will detail our new approaches towards the synthesis of functionalized tetrahydrobenzofurans and chiral α-quaternary α’-hydroxy ketones. The transformations in these approaches were enabled by the chemistries of oxyallyl cations, Grignard reaction and Claisen rearrangement. Chapter 1 introduces oxyallyl cations, their generation, reactions and applications. Our previous contributions, in the form of silyloxyallyl cations, to solve the regioselective issues associated with unsymmetrical oxyallyl cations will be discussed. Chapter 2 focuses on our exploration of the synthetic utility of these novel cations toward the biologically relevant heterocyclic compounds known as tetrahydrobenzofurans. Chapter 3 provides a short review of Claisen rearrangement, describing its catalysis and applications. Grignard reactions and their enantioselectivity will also be presented followed by our application of these traditional methods to the diastereoselective and enantioselective construction of chiral α-quaternary α’-hydroxy ketones. Studies for a complete mechanistic insight on this reaction is ongoing in our lab. It is noteworthy to mention that our new methods described in Chapter 2 and 3 are robust, operationally simple, gave the desired compounds in good yields, and are tolerated by a broad scope of substrates