Tetrahydrofuran amino acids: Secondary structure in tetrameric and octameric carbopeptoids derived from a D-allo 5-(aminomethyl)tetrahydrofuran-2-carboxylic acid

The synthesis of a D-allo-5-(azidomethyl)tetrahydrofuran-2-carboxylate as a n amino acid precursor (in which the carboxylic acid is cis to the azidomet hyl substituent and trans to the diol moiety) is reported from D-ribose. Th e oligomerisation of this monomer to dimeric, tetrameric and octameric carb opeptoids is described. NMR studies into the solution structures of cyclohe xylidene-protected oligomers and of a deprotected tetramer with eight free hydroxy groups are described.