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. 2010 Nov 30;107(48):20648-51.
doi: 10.1073/pnas.1002845107. Epub 2010 Oct 4.

Direct and enantioselective {alpha}-allylation of ketones via singly occupied molecular orbital (SOMO) catalysis

Anthony Mastracchio  1 , Alexander A Warkentin, Abbas M Walji, David W C MacMillan
Affiliations

Direct and enantioselective {alpha}-allylation of ketones via singly occupied molecular orbital (SOMO) catalysis

Anthony Mastracchio et al. Proc Natl Acad Sci U S A. .

Abstract

The first enantioselective organocatalytic α-allylation of cyclic ketones has been accomplished via singly occupied molecular orbital catalysis. Geometrically constrained radical cations, forged from the one-electron oxidation of transiently generated enamines, readily undergo allylic alkylation with a variety of commercially available allyl silanes. A reasonable latitude in both the ketone and allyl silane components is readily accommodated in this new transformation. Moreover, three new oxidatively stable imidazolidinone catalysts have been developed that allow cyclic ketones to successfully participate in this transformation. The new catalyst platform has also been exploited in the first catalytic enantioselective α-enolation and α-carbooxidation of ketones.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme 1.
Scheme 1.
Scheme 2.
Scheme 2.
An evolution of activation modes in organocatalysis.
Scheme 3.
Scheme 3.
Relevant ionization potentials of reactive species; DFT minimized radical cation; representative transformations.
Scheme 4.
Scheme 4.
Selected transformations using SOMO catalysis.
Scheme 5.
Scheme 5.
Initial result of direct ketone allylation.
Scheme 6.
Scheme 6.
Catalyst design and reaction efficiency.
Scheme 7.
Scheme 7.
General utility of ketone α-functionalization.
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