Catalytic, Enantioselective Aldol Additions to Ketones
- 28 March 2002
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 124 (16) , 4233-4235
- https://doi.org/10.1021/ja025670e
Abstract
Catalytic, enantioselective additions of a trichlorosilyl ketene acetal to ketones have been demonstrated. The trichlorosilyl enolate of methyl acetate undergoes a rapid and high-yielding aldol addition to a wide range of ketones (aromatic, olefinic, acetylenic, aliphatic) in the presence of a catalytic amount of pyridine N-oxide. Moreover, in the presence of a catalytic amount (10 mol %) of a chiral bispyridine bis N-oxide (possessing both axial and central chiral elements) the aldol addition takes place again in excellent yield and with good stereoselectivity. The enantioselectivities of the additions are highly variable (7−86% ee) and are strongly dependent on the structure of the ketone acceptor. Aromatic methyl ketones gave the highest selectivity, whereas olefinic ketones were the least selective.Keywords
This publication has 17 references indexed in Scilit:
- On the Mechanism of Catalytic, Enantioselective Allylation of Aldehydes with Chlorosilanes and Chiral Lewis BasesJournal of the American Chemical Society, 2000
- Kinetic Analysis of the Divergence of Reaction Pathways in the ChiralLewis Base Promoted Aldol Additions of Trichlorosilyl Enol Ethers: A Rapid-Injection NMR StudyHelvetica Chimica Acta, 2000
- A Novel Synthesis of a Highly Sterically Hindered C2-Symmetric Chiral Pyridine DerivativeHETEROCYCLES, 2000
- C2-Symmetric Copper(II) Complexes as Chiral Lewis Acids. Scope and Mechanism of the Catalytic Enantioselective Aldol Additions of Enolsilanes to Pyruvate EstersJournal of the American Chemical Society, 1999
- (S)-3,3‘-Dimethyl-2,2‘-biquinoline N,N‘-Dioxide as an Efficient Catalyst for Enantioselective Addition of Allyltrichlorosilanes to AldehydesJournal of the American Chemical Society, 1998
- Catalytic Asymmetric Addition of ZnPh2 to Ketones: Enantioselective Formation of Quaternary StereocentersJournal of the American Chemical Society, 1998
- Chemistry of Trichlorosilyl Enolates. 1. New Reagents for Catalytic, Asymmetric Aldol AdditionsJournal of the American Chemical Society, 1996
- Ni(II)/Cr(II)-mediated coupling reaction: an asymmetric processThe Journal of Organic Chemistry, 1995
- Enantioselective Synthesis of Optically Active Pyridine Derivatives and C2‐Symmetric 2,2′‐BipyridinesEuropean Journal of Inorganic Chemistry, 1992
- The interaction of electrophilic silanes (Me3SiX, X = ClO4, I, CF3SO3, Br, Cl) with nucleophiles. The nature of silylation mixtures in solution.Tetrahedron Letters, 1985