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Amino acid-derived catalysts asymmetric hydrogen transfer

Metal-based asymmetric phase-transfer catalysts have mainly been used to catalyze two carbon-carbon bond-forming reactions (1) the asymmetric alkylation of amino acid-derived enolates and (2) Darzens condensations [5]. The alkylation ofprochiral glycine or alanine derivatives [3] is a popular and successful strategy for the preparation of acyclic a-amino acids and a-methyl-a-amino acids respectively (Scheme 8.1). In order to facilitate the generation of these enolates and to protect the amine substituent, an imine moiety is used to increase the acidity of the a-hydrogens, and therefore allow the use of relatively mild bases (such as metal hydroxides) to achieve the alkylation. In the case of a prochiral glycine-derived imine (Scheme 8.1 R3 = H), if monoalkylation is desired, the new chiral methine group... [Pg.161]


See other pages where Amino acid-derived catalysts asymmetric hydrogen transfer is mentioned: [Pg.945]    [Pg.161]    [Pg.109]    [Pg.329]    [Pg.196]    [Pg.305]    [Pg.332]    [Pg.946]    [Pg.332]    [Pg.946]    [Pg.49]    [Pg.244]    [Pg.81]    [Pg.142]   
See also in sourсe #XX -- [ Pg.977 , Pg.978 ]




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Amino acid derivatives

Amino acids deriv

Amino asymmetric hydrogenation

Amino catalyst

Amino-transfer

Asymmetric amino acid derivatives

Asymmetric derivatives

Asymmetric hydrogenation catalysts

Asymmetric transfer

Asymmetric transfer hydrogenation

Asymmetric transfer hydrogenation catalysts

Catalyst asymmetric

Catalyst transfer hydrogenation

Catalysts amino acid

Catalysts transfer

Hydrogen transfer catalyst

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