Palladium-Catalyzed Allylic Alkylation of Aldimine Esters with Vinyl-Cyclopropanes to Yield α,α-Disubstituted α-Amino Acid Derivatives
A synthetically useful approach for the synthesis of functionalized α, α-disubstituted α-amino acid derivatives via palladium-catalyzed 1,7 addition of readily available aldimine esters to vinylcyclopropanes is reported. This methodology was operated under mild conditions, affording α-allylic α-amino esters in good to excellent yields and excellent regio- and stereoselectivity. This transformation displays broad functional-group tolerance and enantioselective allylic alkylation has also been realized using a chiral phosphine ligand to provide the desired product. (Figure presented.).
A method for the solid phase preparation of an amine by a novel synthesis is described where a diol is monoalkylated with a chloromethyl resin followed by reaction with N,N'-carbonyldimidazole to afford a resin-bound tertiary-alkoxycarbonyl-imidazole which is subsequently N-alkylated and then sequentially treated with appropriate building blocks and reagents to afford a resin-bound amine which affords the desired amine after treatment with an acid as well as other valuable intermediates used in the process.
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(2008/06/13)
Synthesis and binding affinities of novel spirocyclic lactam peptidomimetics of somatostatin
Synthesis of novel spirocyclic lactam peptidomimetics of the binding domain of somatostatin from commercially available D, L-methionine is described.