Arene-Mn(CO), cations react with the Schollkopf chiral glycine enolate equivalent (1) or (2) to give dien~l-Mn(C0)~ complexes which are converted to arylglycine methyl esters; the reaction sequence can be performed on aren~?-Mn(CO)~ complexes having protected amino acid substituents to give diaryl ethers having amino ester groups on both aromatic rings.We recently described a method for 0-phenylation of protected tyrosine and 4-hydroxyphenylglycine derivatives using a chlorobenzene-manganese tricarbonyl cation, which proceeded under very mild conditions and without detectable racemisation in the amino acid side chain.' If this chemistry can be developed to allow the construction of diaryl ethers having amino acid groups attached to both aromatic rings, it should provide access to subunits required for the synthesis of complex glycopeptide antibiotics such as vancomycin and ristocetin A,' as well as simpler peptides containing aryl ether linkages.3 We report herein our preliminary studies on the conversion of arene-Mn(C0)3 complexes to aryl glycines via their reaction with the Schollkopf chiral glycine enolate equivalent4 (I) or (2), which proceeds satisfactorily using arene-Mn(C0)3 systems having protected amino acid moieties in the side chain.Initial experiments utilised the simple arene-Mn(C0)3 complexes (3), which were treated with (1) [l equiv.
Diaryl and polyaryl ethers are important subunits in a wide variety of natural products,1 but the commonly used method for constructing the ether linkage, i.e., Ullman coupling,2 proceeds only under quite harsh conditions. One Combustion analyses were determined by Galbraith, Inc.,
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