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Synfacts 2014; 10(9): 0933
DOI: 10.1055/s-0034-1378644
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Dearomative Cycloadditions Catalyzed by Palladium

Contributor(s):
Hisashi Yamamoto
,
Biplab Maji
Trost BM, * Ehmke V, O’Keefe BM, Bringley DA. Stanford University, USA
Palladium-Catalyzed Dearomative Trimethylenemethane Cycloaddition Reactions.

J. Am. Chem. Soc. 2014;
136: 8213-8216
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Publication History

Publication Date:
18 August 2014 (online)

 
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Key words

palladium - nitroarenes - trimethylene-methanes - [3+2] cycloaddition

Significance

The authors describe a palladium-catalyzed enantioselective dearomative trimethyl­enemethane (TMM) [3+2] cycloaddition with three nitroarenes. Chiral phosphoramidite or diamidophosphites were utilized to induce moderate to high levels of enantioselectivities along with high chemical yields. The key significance of this work is the selective tuning of the reactivity and enantio­selectivity of the catalyst system, which enables exclusive formation of the dearomatized products for an intermolecular cycloaddition in high enantio­selectivities.


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Comment

The current catalytic system is unable to induce high levels of enantioselectivities for the unsubstituted TMM donor in contrast to the alkynyl-substituted TMM donor. It was proposed that the alkynyl substituent bonds tightly to the β-carbon of the nitroarene and creates more steric bulk, which enables a higher degree of differentiation between the two prochiral phases in the transition state.


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