Investigations into the reactivity of alkynes and sulfur oxides under gold catalysis

Barrett, Matthew (2016). Investigations into the reactivity of alkynes and sulfur oxides under gold catalysis. University of Birmingham. Ph.D.

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Abstract

Within this thesis sulfur oxides have been reacted under gold catalysis with alkynes allowing access to interesting and novel structures.
The gold catalysed oxyarylation of alkynes with aryl sulfides has been employed, developing conditions for the use of dibenzothiophene-S-oxide as the oxidant for the first time, to enable an efficient way to modify these useful structures. The extension of the methodology allows disubstitution of dibenzothiophenes and a novel oxyarylation-cycloisomerisation cascade. Overall the method showcases very mild conditions and good chemoselectivity.
Secondly a novel gold catalysed reaction of aromatic disulfur oxides with terminal and ester substituted internal alkynes has been developed. Fluorene and naphthalene derived sulfur oxides can be oxidised and functionalised in a single step with a range of terminal alkynes. The transformation successfully exploits rhodium carbene reactivity with alkynes and sulfur oxides.
Finally a large series of alkynyl sulfoxides have been synthesised which can undergo an efficient gold catalysed intramolecular cyclopropanation with an external oxidant affording fused sulfur heterocycles. This work presents the first example of accessing cyclopropanation from an α-diazo sulfoxide, or equivalent. Attempts to access other carbene reactivity modes are discussed as well as the synthesis of highly enantioenriched alkynyl sulfoxides and their treatment under gold catalysis.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):