Synthesis of a conformationally restricted substrate analogue of siderophore biosynthetases

[GRAPHICS] A conformationally restricted analogue (5) of N-omega-acetyl-N-omega-hydroxyornithine and lysine was synthesized. The synthesis features an efficient acylnitroso hetero-Diels-Alder cycloadduct (1) ring opening with palladium(0) and methylnitroacetate.