Synthesis of α-diazo-β-hydroxyesters through a one-pot protocol by phase-transfer catalysis: application to enantioselective aldol-type reaction and diastereoselective synthesis of α-amino-β-hydroxyester derivatives
作者:Kazuya Hasegawa、Shigeru Arai、Atsushi Nishida
DOI:10.1016/j.tet.2005.11.028
日期:2006.2
The one-pot synthesis of α-diazo-β-hydroxyesters from sodium azide under phase-transfer-catalyzed conditions has been achieved. This protocol includes three different chemical transformations promoted by a single catalyst in each step to give products in good to excellent yields. The reaction was applied to a catalytic asymmetric aldol-type reaction using α-diazoesters with aldehydes in the presence
Abstract The aldoladdition of acyldiazomethane with aromatic aldehydes, vinyl aldehyde and aliphatic aldehydes was carried out efficiently in the presence of MgI2 etherate and iPr2EtN (DIPEA) using untreated reagent-grade CH2Cl2 under atmospheric conditions in good to excellent yields. Iodide counterion and a non-coordinating reaction media (i.e. CH2Cl2) are among the critical factors for the unique
Directaldolcondensation of various aromatic, heteroaromatic, α,β-unsaturated aldehydes and aliphatic aldehydes with acyldiazomethane was realized using MgI2 etherate (MgI2·(Et2O)n) as a promoter in the presence of diisopropyl amine (DIPEA) in excellent yields in a short time under mild conditions with high chemoselectivity. Iodide counterion, and a non-coordinating less ploar reaction media (i.e
One-pot synthesis of α-diazo-β-hydroxyesters under phase-transfer catalysis and application to the catalytic asymmetric aldol reaction
作者:Shigeru Arai、Kazuya Hasegawa、Atsushi Nishida
DOI:10.1016/j.tetlet.2003.11.083
日期:2004.1
The one-pot (three steps) synthesis of α-diazo-β-hydroxyesters from tosyl chloride under phase-transfercatalysis is described. The catalytic asymmetric aldol reaction between a diazoester and aldehydes was also investigated and gave moderate to good enantioselectivity.