Functionalisation of sp3 C-O bonds and olefins enabled by nickel catalysis

Identifier:  TDX:4681

Handle: https://hdl.handle.net/20.500.11797/TDX4681

Authors:  Talavera Codina, Laura

Abstract:
In recent years, nickel catalysis has gained considerable momentum as a vehicle to enable bond-forming reactions with exceptional efficiency. This is probably due to the ease at which nickel catalysts trigger single-electron transfer events, activation of strong C-X bonds and functionalisation of pi-components, offering new vistas to promote reactions that would otherwise be difficult to accomplish by other means. In line with our ongoing interest in developing strategies to functionalise strong sigma-bonds and the functionalisation of readily available starting materials, this Doctoral Thesis has been focused on two main areas: i) the functionalisation of unactivated C-O bonds, and ii) the 1,1-difunctionalisation of unactivated olefins. The first study explores the functionalisation of unactivated C-O bonds in cyclic acetals through metallaphotoredox catalysis. The reaction is triggered by an appropriate orbital overlap prior to C-O cleavage, highlighting the significance of conformational flexibility in achieving both reactivity and site selectivity. In a distinct effort, we directed our attention towards the 1,1-difunctionalisation of olefins using nickel catalysis. Unlike the extensively studied 1,2-difunctionalisation of alkenes, we recognised that the development of a platform that might enable 1,1-difunctionalisation of olefins would expand the repertoire of bond disconnections available in modern organic synthesis. Initially we demonstrated the synthesis of bis-organometallic reagents bearing both B and Si motifs. Building upon the success of this transformation, we envisioned the development of a generic platform for synthesising alpha-aminoboronic acids.