Disulfonimide‐Catalyzed Asymmetric Reduction of
<i>N</i>
‐Alkyl Imines
作者:Vijay N. Wakchaure、Philip S. J. Kaib、Markus Leutzsch、Benjamin List
DOI:10.1002/anie.201504052
日期:2015.9.28
A chiral disulfonimide (DSI)‐catalyzedasymmetric reduction of N‐alkyl imines with Hantzsch esters as a hydrogen source in the presence of Boc2O has been developed. The reaction delivers Boc‐protectedN‐alkyl amines with excellent yields and enantioselectivity. The method tolerates a large variety of alkyl amines, thus illustrating potential for a general reductive cross‐coupling of ketones with diverse
Tandem β-Alkylation−α-Arylation of Amines by Carbolithiation and Rearrangement of <i>N</i>-Carbamoyl Enamines (Vinyl Ureas)
作者:Jonathan Clayden、Morgan Donnard、Julien Lefranc、Alberto Minassi、Daniel J. Tetlow
DOI:10.1021/ja1007992
日期:2010.5.19
an umpolung fashion to the beta-carbon of N-carbamoyl enamines (N-vinyl ureas). The reaction proceeds with syn diastereospecificity and provides urea-stabilized, configurationally defined organolithiums. Facilitated by coordinating solvents (THF or DMPU), these undergo intramolecular attack on an N'-aryl group, resulting in retentive arylation of the organolithium and hence overall addition of an alkyl
Tackling
<i>N</i>
‐Alkyl Imines with 3d Metal Catalysis: Highly Enantioselective Iron‐Catalyzed Synthesis of α‐Chiral Amines
作者:Clemens K. Blasius、Niklas F. Heinrich、Vladislav Vasilenko、Lutz H. Gade
DOI:10.1002/anie.202006557
日期:2020.9.7
catalyzes the highly enantioselective hydroboration of N‐alkyl imines. Employing a chiral bis(oxazolinylmethylidene)isoindoline pincer ligand, the asymmetric reduction of various acyclic N‐alkyl imines provided the corresponding α‐chiral amines in excellent yields and with up to >99 % ee. The applicability of this base metal catalytic system was further demonstrated with the synthesis of the pharmaceuticals
Geometry-Selective Synthesis of <i>E</i> or <i>Z</i> <i>N</i>-Vinyl Ureas (<i>N</i>-Carbamoyl Enamines)
作者:Julien Lefranc、Daniel J. Tetlow、Morgan Donnard、Alberto Minassi、Erik Gálvez、Jonathan Clayden
DOI:10.1021/ol1027442
日期:2011.1.21
N-Vinyl ureas are emerging as a valuable class of compounds with both nucleophilic and electrophilic reactivity. They may be made by capturing the enamine tautomer of an imine with an isocyanate, a reaction which in general leads to the E isomer of the vinyl urea. Deprotonation of such a vinyl urea, or of an allyl urea, generates a dipole stabilized Z-allyl anion which may be protonated to return the Z-vinyl urea. Isomerization of an allyl urea with a Ru complex provides an alternative route to E-vinyl ureas.