Approaches to phorbol and guanacastepene
Nigel P. Bainbridge
2134/33968
https://repository.lboro.ac.uk/articles/thesis/Approaches_to_phorbol_and_guanacastepene/9399164
Dicobalt hexacarbonyl alkyne complexes have been used in organic syntheses to
generate complex organic molecules, with the aim of synthesizing phorbol and
guanacastepene.
In our approaches to both phorbol and guanacastepene we used combinations of three
properties of dicobalt hexacarbonyl complexes. The ability of the dicobalt hexacarbonyl
complex to stabilise propargylic cations, known as Nicholas carbocations, and the ability
of these cations to form carbon-carbon bonds, known as the Nicholas reaction. The formal
[2+2+1] cyclization that dicobalt hexacarbonyl complexes undergo when reacted with
alkenes, to form cyclopentenones known as the Pauson–Khand reaction. The change in
geometry of the alkyne that occurs when the alkyne forms a complex with dicobalt
octacarbonyl, form linear to possessing carbon-carbon bond angles of 140° allowing the
formation of cycloheptyne dicobalt hexacarbonyl complexes. [Continues.]
2018-07-18 08:24:27
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Chemical Sciences not elsewhere classified