Chemo- and diastereoselective Bi(OTf)(3)-catalyzed benzylation of silyl nucleophiles

The direct alkylation of silyl enol ethers with para-methoxybenzylic alcohols or their corresponding acetates was efficiently catalyzed by Bi(OTf)(3) in CH3NO2 as the solvent. The reaction provided the alpha-benzylated carbonyl compounds in high yields after short reaction times using 1-2.5 mol % of...

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Bibliographic Details
Published inTetrahedron letters Vol. 49; no. 8; pp. 1305 - 1309
Main Authors Rubenbauer, Philipp, Bach, Thorsten
Format Journal Article
LanguageEnglish
Published OXFORD Elsevier 18.02.2008
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
facial diastereoselectivity
ENOL ETHERS
ALLYLATION
triethylsilane
ALDEHYDES
ALCOHOLS
KETONES
silyl enol ether
REDUCTION
benzylic alcohols
Bi catalysis
ALPHA-ALKYLATION
FRIEDEL-CRAFTS ALKYLATION
TERT-ALKYLATION
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Summary:The direct alkylation of silyl enol ethers with para-methoxybenzylic alcohols or their corresponding acetates was efficiently catalyzed by Bi(OTf)(3) in CH3NO2 as the solvent. The reaction provided the alpha-benzylated carbonyl compounds in high yields after short reaction times using 1-2.5 mol % of the catalyst. Benzylic acetates other than para-methoxybenzylic acetates also underwent the reaction. High facial diastereoselectivities were observed with acetates derived from chiral alpha-branched para-methoxybenzylic alcohols. In addition, a catalytic reduction with Et3SiH as the reducing agent is reported. (c) 2007 Elsevier Ltd. All rights reserved.
ISSN:0040-4039
DOI:10.1016/j.tetlet.2007.12.092