Synthesis of orthogonally protected biaryl amino acid derivatives.
Org Biomol Chem
; 4(19): 3639-47, 2006 Oct 07.
Article
em En
| MEDLINE
| ID: mdl-16990939
ABSTRACT
The efficient and direct synthesis of protected biaryl amino acids, including dityrosine (50% overall yield over 3 steps), by Negishi cross-coupling of the serine-derived organozinc reagent 4 with iodo- and di-iodobiaryls, is reported. An improved, although still not perfect, diiodination of 2,2'-biphenol has been achieved using NMe3BnICl2-ZnCl2. Protection of phenolic hydroxyl groups as acetates, rather than benzyl ethers, is required for efficient cross-coupling, and evidence for acetyl migration has been observed during debenzylation of a substituted 2-acetoxy-2'-benzyloxybiaryl. Aromatic C-I to C-Cl conversion has been detected as a minor reaction pathway in the palladium-catalyzed coupling of aryl iodide 3b with organozinc reagent 4.
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Base de dados:
MEDLINE
Assunto principal:
Aminoácidos
Idioma:
En
Revista:
Org Biomol Chem
Assunto da revista:
BIOQUIMICA
/
QUIMICA
Ano de publicação:
2006
Tipo de documento:
Article