Chemo-enzymatic synthesis of all isomeric 3-phenylserines and -isoserines
作者:H. Hönig、P. Seufer-Wasserthal、H. Weber
DOI:10.1016/s0040-4020(01)90519-8
日期:1990.1
prepared from cinnamic acid derivatives or viaaldolcondensations of benzaldehyde and suitable enolates in few steps. These racemates were resolved with lipases from Candida cylindracea (CC) and Pseudomonas fluorescens (P) and the obtained products were hydrogenated to 3-phenylserines and -isoserines. The influence of the acyl group in the enzymatic resolution of erythro-3-azido-2-acyloxy-3-phenylpropionic
Indium enolates were readily prepared by transmetalation of lithium enolates with indium trichloride, and were subsequently reacted with aldehydes to give β-hydroxy esters in high yields. Indium α-bromo enolates were also prepared and reacted with carbonyl compounds to give Darzens-type α,β-epoxy carbonyl products.
Towards the development of oxadiazinanones as chiral auxiliaries: synthesis and application of N3-haloacetyloxadiazinanones
作者:Trisha R. Hoover、Jonathan A. Groeper、Raleigh W. Parrott、Seshanand P. Chandrashekar、Jennifer M. Finefield、Alexandro Dominguez、Shawn R. Hitchcock
DOI:10.1016/j.tetasy.2006.06.036
日期:2006.7
Oxadiazinanones derived from (1R,2S)-ephedrine and (1R,2S)-norephedrine were employed in the asymmetric alpha-halo aldol reaction. The optimized yields and diastereoselectivities for the ephedrine based oxadiazinanone aldol reaction ranged from fair to good. The ephedrine based aldol adducts were hydrolyzed to afford the alpha-bromo-beta-hydroxycarboxylic acids. The absolute stereochemistry and enantiomeric purity of these products were determined by chiral HPLC and specific rotation measurements. (c) 2006 Elsevier Ltd. All rights reserved.