Article

Direct-type catalytic three-component mannich reactions leading to an efficient synthesis of alpha,beta-diamino acid derivatives.

Graduate School of Pharmaceutical Sciences, The University of Tokyo, The HFRE Division, ERATO, Japan Science and Technology Corporation (JST), Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Organic Letters (impact factor: 5.86). 09/2006; 8(16):3533-6. DOI:10.1021/ol0613012
Source: PubMed

ABSTRACT [reaction: see text] The first example of the Lewis acid-catalyzed three-component direct-type Mannich reaction of simple aromatic and enolizable aliphatic aldehydes, secondary amines, and glycine derivatives is described. The procedure is highly atom economical and can be performed in a simple one-pot operation under mild conditions to afford a wide variety of synthetically important anti-alpha,beta-diamino ester derivatives in high yields with high diastereoselectivities.

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  • Article: Three-component Ag-catalyzed enantioselective vinylogous mannich and Aza-Diels-Alder reactions with alkyl-substituted aldehydes.
    Hiroki Mandai, Kyoko Mandai, Marc L Snapper, Amir H Hoveyda
    [show abstract] [hide abstract]
    ABSTRACT: Efficient protocols for three-component catalytic enantioselective vinylogous Mannich (VM) reactions of alkyl-substituted aldimines (including those bearing heteroatom-containing substituents) and readily available siloxyfurans are presented. High efficiency and stereoselectivity is achieved through the use of o-thiomethyl-p-methoxyaniline-derived aldimines. Reactions, performed under an atmosphere of air and in undistilled THF, can be promoted in the presence of as little as 1 mol % of easily accessible amino acid-based chiral ligands and commercially available AgOAc. The desired products are obtained in 44 to 92% yield, and in up to >98:<2 diastereomer and >99:<1 enantiomer ratio (>98% ee). Removal of the N-activating group is performed through a one-vessel oxidation/hydrolysis operation, which proceeds via a stable aza-quinone (characterized by X-ray crystallography). Evidence is presented indicating that reactions with chiral nonracemic aldehydes are subject to catalyst control: both substrate enantiomers react to afford the desired product diastereomers in high stereoselectivity. Aryl- and alkynyl-substituted o-thiomethyl-p-methoxyaniline-derived aldimines undergo Ag-catalyzed enantioselective VM reactions more efficiently and with higher selectivity than the corresponding o-anisidyl substrates. Additionally, Ag-catalyzed aza-Diels-Alder reactions of the alkyl-substituted aldimines bearing the structurally modified N-aryl unit afford enantiomerically enriched (up to 95% ee) products in up to 88% yield.
    Journal of the American Chemical Society 12/2008; 130(52):17961-9. · 9.91 Impact Factor
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Keywords

enolizable aliphatic aldehydes
 
glycine derivatives
 
Lewis acid-catalyzed three-component direct-type Mannich reaction
 
mild conditions
 
simple one-pot operation
 
text]
 
wide variety
 

Matthew M Salter