Direct Catalytic Asymmetric Mannich-Type Reactions of γ-Butenolides: Effectiveness of Brønsted Acid in Chiral Metal Catalysis

Direct catalytic asymmetric Mannich-type reactions of γ-butenolides are described. A chiral Lewis acid/amine base/Brønsted acid combination was used to catalyze a γ-addition of γ-butenolides to N-diphenylphosphinoyl imines, affording the products in up to >99% yield, anti/syn = >97:3, and 84%...

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Published inOrganic letters Vol. 10; no. 11; pp. 2319 - 2322
Main Authors Yamaguchi, Akitake, Matsunaga, Shigeki, Shibasaki, Masakatsu
Format Journal Article
LanguageEnglish
Published WASHINGTON American Chemical Society 05.06.2008
Amer Chemical Soc
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Summary:Direct catalytic asymmetric Mannich-type reactions of γ-butenolides are described. A chiral Lewis acid/amine base/Brønsted acid combination was used to catalyze a γ-addition of γ-butenolides to N-diphenylphosphinoyl imines, affording the products in up to >99% yield, anti/syn = >97:3, and 84% ee. The use of a catalytic amount of TfOH in addition to La(OTf)3/Me-PyBox/TMEDA was important for improving yield and stereoselectivity.
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ISSN:1523-7060
1523-7052
DOI:10.1021/ol800756r