The synthesis and reactivity of azazirconacycles
The synthesis and reactivity of azazirconacycles
The zirconocene and titanocene mediated cyclisation of alkenes and non-conjugated dienes is reviewed and an introduction to the reactions of zirconocene η2-imine and η2-ketone complexes is given.
The preparation of η2-imine complexes of zirconocene by a novel rearrangement route is described. The reaction involves the insertion of isocyanides into zirconacyclopentanes or -pentenes derived from zirconocene mediated cyclisation of α, ω-dienes or -enynes respectively. The resultant cyclic iminoacyl complexes of zirconocene undergo a facile 1,2-migration to give the required zirconocene η2-imine complexes. The η2-imine complexes insert (carbometallate) a range of alkenes and alkynes with good regiocontrol providing access to a range of stereodefined bicyclic amine products upon work-up. Phenylamino products derived from zirconacyclopentene precursors undergo an unprecedented anti-1,3-phenylamino shift either spontaneously or during chromatography on silica gel to give 1-anilino-cis-bicyclo[3.3.0]oct-2-enes.
A range of novel 1-azadiene complexes of zirconocene were prepared by a direct complexation route from 1-aza-1,3-butadienes and by a C-H activation route from allylic amines. The complexes are best described as 1-zircona-2-azacyclopent-3-enes and adopt a bent envelope conformation in solution. 5-Unsubstituted examples are fluxional and their dynamic NMR properties were investigated.
University of Southampton
1994
Davis, Jeremy Martin
(1994)
The synthesis and reactivity of azazirconacycles.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The zirconocene and titanocene mediated cyclisation of alkenes and non-conjugated dienes is reviewed and an introduction to the reactions of zirconocene η2-imine and η2-ketone complexes is given.
The preparation of η2-imine complexes of zirconocene by a novel rearrangement route is described. The reaction involves the insertion of isocyanides into zirconacyclopentanes or -pentenes derived from zirconocene mediated cyclisation of α, ω-dienes or -enynes respectively. The resultant cyclic iminoacyl complexes of zirconocene undergo a facile 1,2-migration to give the required zirconocene η2-imine complexes. The η2-imine complexes insert (carbometallate) a range of alkenes and alkynes with good regiocontrol providing access to a range of stereodefined bicyclic amine products upon work-up. Phenylamino products derived from zirconacyclopentene precursors undergo an unprecedented anti-1,3-phenylamino shift either spontaneously or during chromatography on silica gel to give 1-anilino-cis-bicyclo[3.3.0]oct-2-enes.
A range of novel 1-azadiene complexes of zirconocene were prepared by a direct complexation route from 1-aza-1,3-butadienes and by a C-H activation route from allylic amines. The complexes are best described as 1-zircona-2-azacyclopent-3-enes and adopt a bent envelope conformation in solution. 5-Unsubstituted examples are fluxional and their dynamic NMR properties were investigated.
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Published date: 1994
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Local EPrints ID: 462633
URI: http://eprints.soton.ac.uk/id/eprint/462633
PURE UUID: b3a7e985-6ed3-44a6-ae1d-97be376b70dc
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Date deposited: 04 Jul 2022 19:34
Last modified: 04 Jul 2022 19:34
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Author:
Jeremy Martin Davis
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