M. Oba et al., STEREOSELECTIVE DEUTERIUM-LABELING OF DIASTEREOTOPIC METHYL AND METHYLENE PROTONS OF L-LEUCINE, Tetrahedron letters, 39(12), 1998, pp. 1595-1598
An asymmetric synthesis of regio-and stereoselectively deuterium-label
led L-leucine was examined using 4-hydoxy-L-poline as a chiral templat
e. An enol triflate of 4-oxoproline prepared from 4-hydroxyproline was
effectively methylated by a Gilman reagent to afford a 4-methyl-3,4-d
ehydroproline derivative. Then, a catalytic deuteration of the dehydro
proline followed by RuO4-oxidation gave a deuterated 4-methylpyrogluta
mic acid derivative that could easily be converted to (2S,3S,4R)-leuci
ne-3,4,5,5-d(5) via a base-promoted ring opening and a reductive deute
ration of the terminal carboxyl moiety. This strategy wits also applie
d to the stereoselective synthesis of (2S,3S,4S)-[3,4,5,5,5-D-5]leucin
e. (C) 1998 Elsevier Science Ltd. All rights reserved.