here a palladium(II)-catalyzed oxidative cyclization reaction of N-allylimines derived from methyl ketones, typically acetophenones, affording pyrrole derivatives at room temperature under oxygen atmosphere. The reaction likely proceeds through α-palladation of the imine followed by olefin migratory insertion and β-hydride elimination, thus representing a new example of aerobicdehydrogenative Heck cyclization
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
The palladium-catalyzed cross-couplingreaction of alkenyl bromides with secondary and primary amines gives rise to enamines and imines, respectively. This new transformation expands the applicability of palladium-catalyzed C-N bond forming reactions (the Buchwald-Hartwig amination), which have mostly been applied to aryl halides. After screening of different ligands, bases, and solvents, the catalytic
Enantioselective Catalytic Addition of HCN to Ketoimines. Catalytic Synthesis of Quaternary Amino Acids
作者:Petr Vachal、Eric N. Jacobsen
DOI:10.1021/ol005636+
日期:2000.3.1
Highly enantioselective addition of HCN to ketoimines has been achieved for the first time using readily accessible and recyclable Schiff base catalysts. Essentially quantitative isolated yield and enantioselectivity of up to 95% ee was obtained. Furthermore, some of the Strecker adducts could be recrystallized in high recovery, yielding optically pure materials. Conversion of the alpha-aminonitrile adducts to the corresponding alpha-quaternary alpha-amino acids was effected in high yield by a formylation/hydrolysis sequence.
Thermal electrocyclic reactions of 2-aza-1,3-butadiene derivatives. A new N-heterocyclic annelation