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. 2005 Dec 14;127(49):17180-1.
doi: 10.1021/ja055968f.

Palladium-catalyzed asymmetric allylic alpha-alkylation of acyclic ketones

Barry M Trost  1 , Jiayi Xu
Affiliations

Palladium-catalyzed asymmetric allylic alpha-alkylation of acyclic ketones

Barry M Trost et al. J Am Chem Soc. .

Abstract

The first example of Pd-catalyzed asymmetric allyl alkylation of the conformationally nonrigid acyclic ketone enolates is reported with excellent yields, regioselectivity, and enantioselectivity. The double bond geometry of the allyl enol carbonates affects its reactivity, selectivity, as well as the absolute configuration of the products. An opposite enantioselectivity from what is predicted by a direct attack of the enolate on the allyl moiety of the pi-ally-Pd complex was observed. An alternative mechanism was proposed, which involves an inner sphere process of coordination of the enolate to Pd followed by reductive elimination.

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Figures

Scheme 1
Scheme 1
Double bond geometry controls the configuration and enatiomeric excess of product.
Scheme 2
Scheme 2
Model for the enantioselectivity of 4.
Scheme 3
Scheme 3
Proposed mechanism for the reaction.
See this image and copyright information in PMC

References

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