A practical and simple synthesis of (2S,5R)- and (2S,5S)-5-hydroxylysine and of a related alpha-amino acid required for the synthesis of the collagen cross-link pyridinoline

A four step synthesis of (2S,5R)- and (2S,5S)-5-hydroxylysine using Williams' glycine template methodology for controlling the stereogenicity at the alpha-position is reported. This route offers the possibility for the synthesis of all possible isomers of 5-hydroxylysine and of an important alpha-amino acidic iodohydrin required for the construction of the hydroxylated side chain of the collagen cross-link pyridinoline.