Functionalization of strong sigma bonds by Nickel and Tungsten catalysis

Identificador:  TDX:3377

Handle: https://hdl.handle.net/20.500.11797/TDX3377

Autors:  Martín Montero, Raúl

Resum:
During last years, the functionalization of strong sigma bonds by transition metal catalysis has gathered exponential attention in the organic chemistry field. Especially, the scission of C–O, C–N and C–H bonds has been targeted due to the prevalence of these bonds in nature, agrochemicals and material science, among others, and the necessity to fulfil novel strategies that offer chemists new tools for future endeavours. Alcohols and amines possess a high activation barrier for C–O and C–N catalytic cleavage, which has prompted the use of derivatives to overpass this limitation. In this line, this Doctoral Thesis presents the utilization of secondary benzyl pivalates and pyridinium salt as partners in nickel catalyzed cross-coupling reactions for the formation of new C–Heteroatom and C–C bonds, respectively. In one side, a new methodology for the first nickel-catalyzed stereospecific borylation of secondary benzyl pivalates is presented. On the other hand, the functionalization of unactivated alkyl amines via the formation of pyridinium salts is demonstrated and allows the deaminative arylation of sp3 carbon centers catalyzed by nickel. Finally, spurred by the ubiquitous prevalence of C–H bonds in nature we focused our efforts toward the activation of such bonds. Despite nickel catalysis has demonstrated its utility and efficiency, this dissertation envisioned the utilization of tungsten catalysis in the field of remote functionalization of C–H bonds that would lead to new transformations. Gratefully, site-selective β-hydroboration of C–H bonds by the utilization of alkene amides catalyzed by tungsten is shown herein.