Organocatalytic synthesis of Pentafulvene derivatives and kinetic analysis of copper catalyzed 1,4-addition

Nouch, Ryan (2020) Organocatalytic synthesis of Pentafulvene derivatives and kinetic analysis of copper catalyzed 1,4-addition. PhD thesis, University of Nottingham.

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Chapter 1 discloses a novel organocatalytic method for the synthesis of pentafulvenes bearing chiral pendant groups. Despite the widespread utility of pentafulvenes, synthetic methods towards them have not developed significantly since their initial discovery in 1900. More specifically, syntheses of pentafulvenes bearing pendant chiral groups are extremely uncommon. The primary aim of this work was to develop the asymmetric synthesis of pentafulvene 1.162a. Novel pentafulvene (±)-1.162a was observed to form in the pyrrolidine catalyzed reaction between 2-acetylbenzaldehyde (1.160a) and CpH. It was envisaged that an enantioselective variant of this reaction could help to furnish 1.162a as a single enantiomer, utilizing the fact that 1.162a was found to crystallize as a conglomerate. This resulted in the chiral amplification of scalemic mixtures of 1.162a to enantiopure 1.162a during crystallization. The reduction of enantiopure 1.162a to the corresponding CpH derivative could then be performed in a diastereoselective manner. This provided a novel, facile method to afford a structurally diverse library of chiral CpH derivatives.

Chapter 2 discloses a data intensive investigation into the kinetics of copper catalyzed 1,4-asymmetric addition using organoaluminium and diorganozinc reagents. Copper catalyzed asymmetric conjugate addition reactions are among the most common methods for enantioselective carbon-carbon bond formation. However there remains little mechanistic evidence to support the structure of their key, rate-determining transition states. The aim of this project was to provide high quality kinetic data on the copper catalyzed asymmetric conjugate addition of organoaluminium and diorganozinc reagents to 2-cyclohexen-1-one. This also lead to the development of a novel copper(I) complex that proved to be an extremely effective catalyst for the asymmetric conjugate addition of organozinc reagents to a variety of α,β-unsaturated ketones. Studies of the copper(II) acetate catalyzed addition of triethylaluminium and the copper(I) tetrakisacetonitrile trifluoroacetate catalyzed addition of diethyl zinc to 2-cyclohexen-1-one were performed.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Woodward, Simon
Keywords: Pentafulvenes, Copper catalyzed 1,4- asymmetric addition
Subjects: Q Science > QD Chemistry
Faculties/Schools: UK Campuses > Faculty of Science > School of Chemistry
Item ID: 59751
Depositing User: Nouch, Ryan
Date Deposited: 31 Jul 2020 04:40
Last Modified: 31 Jul 2020 04:40

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