Stereoselective synthesis of L ‐[2,3,4,5‐D 4 ] ornithine

Synthesis of L ‐[2,3,4,5‐D 4 ]ornithine in which all of the diastereotopic hydrogens were stereoselectively labeled with deuterium was investigated. The chirally deuterated 3‐aminopropanal derivative, a key intermediate in this synthesis, was prepared by a catalytic deuteration of an unsaturated γ‐lactone derived for L ‐glutamic acid followed by several functional group interconversions. Condensation of the obtained deuterium‐labeled 3‐aminopropanal derivative with a chiral glycine template afforded unsaturated ornithine. The dehydroornithine was then subjected to a catalytic deuteration followed by deprotection to give the L ‐[2,3,4,5‐D 4 ]ornithine. Copyright © 2002 John Wiley & Sons, Ltd.