Stereoselective synthesis of β-hydroxy-α-amino acids from chiral cyanohydrins.
摘要:
An efficient one-pot reduction-transimination-hydrocyanation synthesis of beta-hydroxy-alpha-cyanoamines 3 from optically active O-protected mandelonitrile (1) is described. These beta-hydroxy-alpha-cyanoamines were easily converted into optically active (2S,3R) beta-hydroxy-alpha-amino acids 6.
A one-pot reduction-transimition-reduction synthesis of N-substituted β-ethanolamines from cyanohydrins
作者:Peter Zandbergen、Adrianus M.C.H. van den Niewendijk、Johannes Brussee、Arne van der Gen、Chris G. Kruse
DOI:10.1016/s0040-4020(01)88477-5
日期:1992.1
An efficient (74% – 97% yield) three-step one-pot synthesis of (R)-Halostachine and analogues from O-protected opticallyactive cyanohydrins is described. The reaction sequence involves a DIBAL reduction of the nitrile to an imine, transimination to a secondary imine and sodium borohydride reduction to the corresponding N-substituted β-ethanolamine. Both O-protected as well as unprotected reaction
Enantioselective Chemoenzymatic Synthesis of <i>cis-</i> and <i>trans</i>-2,5-Disubstituted Morpholines
作者:Bas Ritzen、Steven Hoekman、Elena Durán Verdasco、Floris L. van Delft、Floris P. J. T. Rutjes
DOI:10.1021/jo1003295
日期:2010.5.21
A versatile synthesis of enantiomerically pure cis- and trans-2,5-disubstituted morpholines is described. Hydroxynitrile lyase-mediated cyanide addition onto aldehydes provided cyanohydrins in virtually quantitative yield and excellent enantioselectivity. Subsequent formation of diastereomerically pure amino esters via a three-step, one-pot reduction-transimination-reduction sequence followed by reduction and simultaneous protection provided cyclization precursors. Finally, cyclization and SmI2-mediated reductive detosylation completed the synthesis of cis- and trans-2,5-disubstituted morpholines in good yields and excellent diastereoselectivities.
Direct conversion of chiral cyanohydrins to chiral nitrones by transimination
作者:Edith Hulsbos、Jan Marcus、Johannes Brussee、Arne van der Gen
DOI:10.1016/s0957-4166(97)00066-9
日期:1997.4
A new method for the preparation of enantiomerically pure N-benzyl nitrones is described. By using either a one-pot reduction-transimination or a one-pot Grignard addition-transimination sequence chiral O-protected alpha-hydroxynitriles can be converted into chiral aldo- and ketonitrones, respectively. (C) 1997 Elsevier Science Ltd.