A practical route to long-chain non-natural α,ω-diamino acids

An efficient method for the synthesis of long-chain \u3b1,\u3c9-diamino acids, starting from natural \u3b1-amino acids, has been developed. The long-chain skeleton has been generated through condensation between a protected aldehyde, derived from l-aspartic acid, and an ylide obtained from an \u3c9-hydroxy-alkyl phosphonium salt. After conversion of the \u3c9-hydroxy group into an amine, catalytic hydrogenation produced the N, N\u2032-protected \u3b1,\u3c9-diamino acid. The present route to \u3b1,\u3c9-diamino acids allows the modulation of the chain length depending on the length of the ylide used for the Wittig olefination reaction