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. 2011 Aug 31;133(34):13248-51.
doi: 10.1021/ja204331w. Epub 2011 Aug 4.

Chiral Brønsted acid from a cationic gold(I) complex: catalytic enantioselective protonation of silyl enol ethers of ketones

Cheol Hong Cheon  1 , Osamu Kanno, F Dean Toste
Affiliations

Chiral Brønsted acid from a cationic gold(I) complex: catalytic enantioselective protonation of silyl enol ethers of ketones

Cheol Hong Cheon et al. J Am Chem Soc. .

Abstract

A chiral Brønsted acid has been developed from a cationic gold(I) disphosphine complex in the presence of alcoholic solvent and applied to the enantioselective protonation reaction of silyl enol ethers of ketones. Various optically active cyclic ketones were obtained in excellent yields and high enantioselectivities, including cyclic ketones bearing aliphatic substrates at the α-position. Furthermore, the application of this Brønsted acid was extended to the first Brønsted acid-catalyzed enantioselective protonation reaction of silyl enol ethers of acyclic substrates, regardless of their E/Z ratio.

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Figures

Figure 1
Figure 1
Enantioselectivity and E/Z ratio during protonation reaction of 6a with LBA.
See this image and copyright information in PMC

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