Nickel/bis(oxazoline)-catalyzed asymmetric Kumada reactions of alkyl electrophiles: Cross-couplings of racemic α-bromoketones

Journal of the American Chemical Society

Volumn 132, Issue 4, 2010, Pages 1264-1266

  Lou, Sha ^a   Fu, Gregory C ^a  

^a MASSACHUSETTS INSTITUTE OF TECHNOLOGY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ALKYLATION; HYDROCARBONS; KETONES; NITROGEN COMPOUNDS; SYNTHESIS (CHEMICAL);

ASYMMETRIC CATALYSIS; ASYMMETRIC SYNTHESIS; BROMOKETONES; CHEMICAL EQUATIONS; CROSS-COUPLINGS; ELECTROPHILES; ENANTIOSELECTIVE COUPLING; GRIGNARD REAGENT; LOW TEMPERATURES; NEW OPPORTUNITIES; OXAZOLINES;

COUPLINGS;

ALPHA BROMOKETONE; ELECTROPHILE; GRIGNARD REAGENT; KETONE; NICKEL; OXAZOLINE DERIVATIVE; UNCLASSIFIED DRUG; BROMINE DERIVATIVE; OXAZOLONE; TRIFLUOROMETHYLOXAZOLINONE;

ARTICLE; ASYMMETRIC CROSS COUPLING REACTION; ASYMMETRIC KUMADA REACTION; CHEMICAL REACTION; CHEMICAL STRUCTURE; CROSS COUPLING REACTION; ENANTIOMER; ENANTIOSELECTIVITY; LOW TEMPERATURE PROCEDURES; SYNTHESIS; ANALOGS AND DERIVATIVES; CATALYSIS; CHEMISTRY; STEREOISOMERISM;

BROMINE COMPOUNDS; CATALYSIS; KETONES; NICKEL; OXAZOLONE; STEREOISOMERISM;

EID: 77950503735     PISSN: 00027863     EISSN: 15205126     Source Type: Journal    
DOI: 10.1021/ja909689t     Document Type: Article

References (43)

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34. 2 • glyme); in the absence of the bis(oxazoline) ligand, the product is generated in 22% yield; the ee of the product is constant during the cross-coupling; in a competition experiment, an unactivated alkyl bromide is recovered in essentially quantitative yield; and use of a solution of the Grignard reagent in THF results in a somewhat lower ee and yield.
35. (b) The efficiency of this method is sensitive to the steric demand of the coupling partners.
36. (c) α-Chloroketones are not suitable substrates under these conditions.
37. 2O (40 mL), and the combined filtrates were concentrated by rotary evaporation. The resulting residue was purified by flash chromatography.
38. Under our standard conditions, our initial attempts to couple heteroaromatic Grignard reagents such as 2-pyridylmagnesium chloride and 3-thienylmagnesium chloride were not successful.
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