Expanding the scope of enantioselective ferroPHANE-promoted [3+2] annulations with alpha,beta-unsaturated ketones. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Chemistry - A European Journal Année : 2010

Expanding the scope of enantioselective ferroPHANE-promoted [3+2] annulations with alpha,beta-unsaturated ketones.

Résumé

The planar chiral 2-phospha[3]ferrocenophane I has been shown to be the first efficient nucleophilic organocatalyst for the enantioselective synthesis of cyclopentenylphosphonates, through [3+2] cyclizations between diethyl allenylphosphonate and alpha,beta-unsaturated ketones. The same catalyst has also been applied to the highly enantioselective [3+2] cyclizations of allenic esters with dibenzylideneacetone and analogous bis-enones, leading to functionalised cyclopentenes with either monocyclic or spirocyclic structures (ee 84-95 %). It has been shown that the residual enone functions in the resulting cyclopentenes can be involved in subsequent cyclization steps to afford unprecedented C(2)-symmetric bis-cyclopentenylketones. In order to provide insight into the behaviour of FerroPHANE I as a chiral catalyst in [3+2] cyclisations, the energetically most favoured isomers of the key phosphine-allene adduct have been calculated by DFT methods. Factors likely to control the chiral induction process are highlighted.

Dates et versions

hal-00454126 , version 1 (08-02-2010)

Identifiants

Citer

Nathalie Pinto, Mathilde Neel, Armen Panossian, Pascal Retailleau, Gilles Frison, et al.. Expanding the scope of enantioselective ferroPHANE-promoted [3+2] annulations with alpha,beta-unsaturated ketones.. Chemistry - A European Journal, 2010, 16 (3), pp.1033-45. ⟨10.1002/chem.200901893⟩. ⟨hal-00454126⟩
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