Cross-Metathesis of Chiral N-tert-Butylsulfinyl
Homoallylamines: Application to the Enantioselective Synthesis of
Naturally Occurring 2,6-cis-Disubstituted Piperidines
traceless activation reagent, a general iridium-catalyzed asymmetrichydrogenation of isoquinolines and pyridines is developed with up to 99% ee. This method avoids tedious steps of installation and removal of the activating groups. The mechanism studies indicated that hydrogen halide generated in situ acted as an activator of isoquinolines and pyridines.
A salt formation strategy for asymmetrichydrogenation of pyridines is described. Poly-substituted pyridiniumsalts were successfully hydrogenated using chiral iridium dinuclear complexes to afford...
Regio- and Stereoselective Monoamination of Diketones without Protecting Groups
作者:Robert C. Simon、Barbara Grischek、Ferdinand Zepeck、Andreas Steinreiber、Ferdinand Belaj、Wolfgang Kroutil
DOI:10.1002/anie.201202375
日期:2012.7.2
Hitting the right target: Differentiation between two keto moieties was accomplished by a regio‐ and enantioselective bioamination employing ω‐transaminases. Using 1,5‐diketones as substrates gave access to the opticallypure 2,6‐disubstituted piperidine scaffold. The approach allowed the shortest synthesis of the alkaloid dihydropinidine, as well as its enantiomer, by choosing an appropriate ω‐transaminase
One-Pot Cascade Synthesis of Mono- and Disubstituted Piperidines and Pyrrolidines using Carboxylic Acid Reductase (CAR), ω-Transaminase (ω-TA), and Imine Reductase (IRED) Biocatalysts
作者:Scott P. France、Shahed Hussain、Andrew M. Hill、Lorna J. Hepworth、Roger M. Howard、Keith R. Mulholland、Sabine L. Flitsch、Nicholas J. Turner
DOI:10.1021/acscatal.6b00855
日期:2016.6.3
Access to enantiomerically pure chiral mono- and disubstituted piperidines and pyrrolidines has been achieved using a biocatalytic cascade involving carboxylic acid reductase (CAR), ω-transaminase (ω-TA), and imine reductase (IRED) enzymes. Starting from keto acids or keto aldehydes, substituted piperidine or pyrrolidine frameworks can be generated in high conversion, ee, and de in one pot, with each
Stereocontrolled preparation of cis- and rans-2,6-dialkylpiperidines via diastereoselective reaction of 1-aza-4-oxabicyclo[4.3.0]nonane derivatives with Grignard reagents
We report here the syntheses of cis- and trans-2,6-disubstituted piperidines using chiral 1-aza-4-oxabicyclo[4.3.0]nonane synthon 1, which shows high reactivity toward nucleophilic attack at its C-5 position. Bicyclic compounds resembling synthon 1 were transformed to cis- and trans-2,6-disubstituted piperidine derivatives via reactions with various Grignard reagents in a stereospecific manner. Using