Improved Isotopic Deuterium Labeling at the Diastereotopic Methyl Group of Leucine: a Synthetic Route to (4<i>S</i>)- and (4<i>R</i>)-[5-<sup>2</sup>H<sub>1</sub>]Leucine
作者:Noriaki YAMAUCHI、Satoshi ENDOH
DOI:10.1271/bbb.70.276
日期:2006.1
Two isotopomers of deuterium-labeled leucine in the diastereotopic methyl group were synthesized from inexpensively available (R)- and (S)-citronellol in a more convenient way than by previous methods.
An enantioselective route for oxazoline 4, a key fragment toward the asymmetric synthesis of leiodelide A, is described. We synthesized northern subunit 6 through a Julia-Lythgoe olefination and subsequent Sharpless asymmetric dihydroxylation. Moreover, a highly diastereoselective method using well-established Evans' asymmetric aldol condensation was developed for preparation of southern fragment 5. The additional feature of this synthetic route is the formation of oxazoline 4 through DAST-promoted cyclization of the amidation product from subunits 5 and 6. (C) 2014 Elsevier Ltd. All rights reserved.