Chemoselective Nucleophilic Attack on N-Acyl Derivatives of (S)-Ethyl 4,4-Dimethyl Pyroglutamate (DMPG)
摘要:
[GRAPHICS]Heteronucleophiles and C-nucleophiles chemoselectively react with n-acyl (S)-ethyl 4,4-dimethyl pyroglutamate (DMPG) affording esters, amides, and ketones in high yield. The intramolecular process allows the stereoselective formation of beta-hydroxy acids likely by formation and ring opening of the corresponding beta-lactones.
catalyze the enantioselective aldol reaction of aldehydes with ketene silyl acetals in DMF at roomtemperature. The platinum(II) complex-catalyzed the enantioselective aldol reaction of aldehydes with 1-methoxy-2-methyl-(1-trimethylsilyloxy)propene gave the corresponding aldols in high yields with enantioselectivity up to 92%. With 5 mol % loading of the complexes, the enantioselective aldol reaction of aldehydes
Catalytic Generation of Activated Carboxylates: Direct, Stereoselective Synthesis of β-Hydroxyesters from Epoxyaldehydes
作者:Kenneth Yu-Kin Chow、Jeffrey W. Bode
DOI:10.1021/ja047407e
日期:2004.7.1
The catalytic generation of activated carboxylates from epoxyaldehydes enables the direct, stereoselective synthesis of beta-hydroxyesters under mild, convenient reaction conditions. In addition to providing a new method for the synthesis of anti-aldol adducts, this chemistry unveils a mechanistically viable solution to the catalytic, waste-free synthesis of esters.
The E/Z geometry of the enolate component determines face selection of the aldehyde component in chiral diazaborolidine-directed enantioselective aldol coupling
作者:E.J. Corey、Duck-Hyung Lee
DOI:10.1016/s0040-4039(00)60765-7
日期:1993.3
An analysis of the effect of enolate geometry on transition-state energy explains the stereochemistry of aldol reactions of acetate and propionate esters with aldehydes using as reagent the chiral diazaborolidine 1.
A novel DMAP-promoted oxazolidinethione deacylation. Application for the direct conversion of the initial chiral thioimide aldols to various ester protecting groups
作者:Dah-Wei Su、Ying-Chuan Wang、Tu-Hsin Yan
DOI:10.1016/s0040-4039(99)00710-8
日期:1999.5
DMAP (4-(dimethylamino)pyridine) promoted nucleophilic cleavage of the initial chiral thioimide aldols can be directed to form various ester protecting groups without causing racemization of the newly created stereocenters. (C) 1999 Elsevier Science Ltd. All rights reserved.