Asymmetric Preparation of New N,N-Dialkyl-2-amino-1,1,2-triphenylethanol Catalysts and a Kinetic Resolution in the Addition of Diethylzinc to Flavene-3-carbaldehydes
摘要:
Enantiopure N,N-dialkyl-(S)-2-amino-1,1,2-triphenylethanols were prepared using a new synthetic methodology and tested for their ability to catalyze the enantioselective addition of diethylzinc to aldehydes. The structural modification of N- substituents of the catalysts led us to identify N- methyl- N-(S)-1-phenylethyl-substituted 4d as an effective catalyst for the addition. Also disclosed is a kinetic resolution of racemic flavene-3-carbaldehydes with the chiral catalyst.
Convenient asymmetric synthesis of both enantiomers of 3,4-disubstituted 3,4-dihydro-1,4-benzoxazin-2-ones
作者:Eunjee Youk、Wongi Park、Yong Sun Park
DOI:10.1080/00397911.2018.1444769
日期:2018.6.3
ABSTRACT Bothenantiomers of N-substituted 3-arylated 3,4-dihydro-1,4-benzoxazin-2-ones were conveniently synthesized up to 93:7 er based on the dynamic kinetic resolution of either (R)-pantolactone- or l-mandelate-derived α-bromo arylacetates in nucleophilic substitution with N-alkylated 2-aminophenols. GRAPHICAL ABSTRACT
摘要 基于 (R)-泛内酯-或 l 的动态动力学分辨率,N-取代的 3-芳基化 3,4-二氢-1,4-苯并恶嗪-2-酮的两种对映异构体均可方便地合成至 93:7 er。 -扁桃酸衍生的α-溴芳基乙酸酯与N-烷基化2-氨基苯酚亲核取代。图形概要
Dynamic resolution of α-halo chiral esters for the synthesis of 3-substituted piperazin-2-ones
作者:Jung In Jang、Seock Yong Kang、Kyoung Hee Kang、Yong Sun Park
DOI:10.1016/j.tet.2011.06.055
日期:2011.8
Dynamicresolution of α-halo esters derived from five chiral alcohols has been investigated in nucleophilicsubstitution with ethylenediamine nucleophiles. Stereoselective substitution of α-halo esters and following spontaneous cyclization provide a practical protocol for asymmetricsyntheses of 3-substituted piperazin-2-ones up to 94:6 er.
A facile synthesis of optically active C2-symmetric 2,5-disubstituted pyrrolidines and other β,β′-dihydroxyamines
作者:Kevin Koh、Robert N. Ben、T. Durst
DOI:10.1016/0040-4039(94)85057-7
日期:1994.1
has been converted into the di-(R)-pantolactone ester of (S,S)-pyyrolidine-2,5-dicarboxylic acid in two steps. This compound serves as a precursor to C2-symmetric2,5-disubstitutedpyrrolidines. The synthesis of linear C2-symmetricβ,β′-dihydroxyamines starting with α-bromophenylacetic acid and (S)-phenylglycine ethyl ester is also reported.
Reaction of (R)-pantolactone esters of alpha-bromoacids with amines a remarkable synthesis of optically active alpha-amino esters
作者:Kevin Koh、Robert N. Ben、Tony Durst
DOI:10.1016/0040-4039(93)88062-n
日期:1993.7
(R)-Pantolactoneesters of racemic α-bromo acids react with amines to give α-amino esters having the (S)-configuration at the α-carbon in yields which are considerably greater than the 50% expected on the basis of a simple SN2 displacement reaction.
外消旋α-溴酸的(R)-内酯酯与胺反应生成α-碳上具有(S)-构型的α-氨基酯,其收率大大高于简单估算的50%预期S N 2置换反应。
Enantioselective Synthesis of β-Dibenzylamino Alcohols via a Dynamic Kinetic Resolution of α-Halo Acids
作者:Jeff A. O'Meara、Nizar Gardee、Manfred Jung、Robert N. Ben、Tony Durst