Catalytic and Stoichiometric Lewis Acid Participation in Aldehyde Ene Cyclisations

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Title:Catalytic and Stoichiometric Lewis Acid Participation in Aldehyde Ene Cyclisations
Creators:
Braddock, D. Christopher
Brown, John M.
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 65, 5, pp. 741-756
Uncontrolled Keywords:Lewis acids, Stereoselective cyclisations, Aluminium catalysts, Terpenoids, Ene reactions, Aldehydes

Abstract

Racemic 2-isopropyl-2-methylhex-5-enal has been synthesised in order to probe ene cyclisations leading to menthol analogues. The objective was first to discover catalytic conditions for preferential cyclisation to the menthol rather than the neomenthol series and then to develop (dynamic) kinetic resolution procedures which afforded a single enantiomer of product. It was found that catalytic quantities of both Me<sub>2</sub>AlCl and a bulky methylaluminium bis(phenoxide) reagent gave products attributed to a Meerwein-Pondorff-Verley reaction. In this the aldehyde is reduced to a primary alcohol and the ene product oxidised to the corresponding α,β-unsaturated ketone. By contrast, a related bulky chloroaluminium reagent catalysed the ene cyclisation cleanly, but preferentially to the undesired neomenthyl stereoisomer. <p>

Title:Catalytic and Stoichiometric Lewis Acid Participation in Aldehyde Ene Cyclisations
Creators:
Braddock, D. Christopher
Brown, John M.
Uncontrolled Keywords:Lewis acids, Stereoselective cyclisations, Aluminium catalysts, Terpenoids, Ene reactions, Aldehydes
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:65
Number:5
Page Range:pp. 741-756
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20000741UNSPECIFIED
ID Code:1676
Item Type:Article
Deposited On:06 Feb 2009 17:11
Last Modified:06 Feb 2009 16:11

Citation

Braddock, D. Christopher; Brown, John M. (2000) Catalytic and Stoichiometric Lewis Acid Participation in Aldehyde Ene Cyclisations. Collection of Czechoslovak Chemical Communications, 65 (5). pp. 741-756. ISSN 0010-0765

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