N-t-Boc 6-amino-1,11-(20-crown-6)-6,7-dihydro-5H-dibenzo[a,c] cycloheptene-6-carboxylic acid methyl ester, the first prototype of a crown-carrier-axially dissymmetric-α,α-disubstituted glycine

N-t-Boc 6-amino-1,11-(20-crown-6)-6,7-dihydro-5H-dibenzo[a,c]cycloheptene-6-carboxylic acid methyl ester: Boc-[20-C-6]-Bip-OMe 1, a new crown-carrier-α,α-disubstituted glycine with axial dissymmetry and a potential building block for the synthesis of polypeptide supramolecular devices, has been synthesized at the racemic state by phase transfer bis-alkylation of a glycine tert-butyl ester Schiff base with 2,2′- bis-(bromomethyl)-6,6′-dimethoxy-1,1′-diphenyl, followed by demethylation, esterification, N-protection and crown formation upon cyclization of the di-cesium salt of the resulting diphenol with pentaethyleneglycol ditosylate. The title compound: Boc-[20-C-6]-Bip-OMe, has been synthesized at the racemic state by phase transfer bis-alkylation of a glycine tert-butyl ester Schiff base with 2,2′- bis-(bromomethyl)-6,6′-dimethoxy-1,1′-diphenyl, followed by demethylation, esterification, N-protection and cyclisation with crown formation.