Heterogeneous Dipeptide-Catalyzed α-Amination of Aldehydes in a Continuous-Flow Reactor: Effect of Residence Time on Enantioselectivity
作者:Sándor B. Ötvös、Aliz Szloszár、István M. Mándity、Ferenc Fülöp
DOI:10.1002/adsc.201500375
日期:2015.11.16
A solid-supported dipeptide-catalyzedcontinuous-flow process was developed for the direct enantioselectiveα-amination of aldehydes with dibenzyl azodicarboxylate as the electrophilic nitrogen source. With residencetime control as an efficient tool for the fine-tuning of the enantioselectivity, synthetically useful α-hydrazino alcohols were achieved with excellent ees. The packed-bed system proved
Remarkable Reaction Rate and Excellent Enantioselective Direct α-Amination of Aldehydes with Azodicarboxylates Catalyzed by Pyrrolidinylcamphor-Derived Organocatalysts
Remarkable reaction rate and excellent enantioselective direct α-amination of unmodified aldehydes with various azodicarboxylates was catalyzed by pyrrolidinylcamphor organo-catalyst 2a (5 mol-%) to provide the desired aminated products with excellent chemical yields and high to excellent levels of enantioselectivity (up to >99%ee) at 0 °C in CH 2 Cl 2 .
A series of secondary amine–thiourea catalysts derived from l-proline and chiral diamine were prepared and successfully applied to the highly effective and enantioselectiveα-amination of unmodified aldehydes with various azodicarboxylates in excellent yields (up to 99%) and enantioselectivities (up to 99% ee) within a few minutes.
Direct Catalytic Asymmetric α-Amination of Aldehydes
作者:Benjamin List
DOI:10.1021/ja0261325
日期:2002.5.1
The first direct catalytic asymmetric alpha-amination of aldehydes is described herein. alpha-Unbranched aldehydes react in this novel proline-catalyzed reaction with dialkyl azodicarboxylates to give alpha-amino aldehydes in excellent yields and enantioselectivities.
Direct asymmetric α-amination of unmodified aldehydes with azodicarboxylates in ionicliquids in the presence of imidazolium ion-tagged l-proline organocatalyst 1 gives excellent enantioselectivities (up to 98% ee) and high chemical yields. The system can be easily recycled and reused for at least four times without significant loss of yields and enantioselectivity.