Continuous‐Flow Amide and Ester Reductions Using Neat Borane Dimethylsulfide Complex
作者:Sándor B. Ötvös、C. Oliver Kappe
DOI:10.1002/cssc.201903459
日期:2020.4.7
importance in synthetic chemistry, and there are numerous protocols for executing these transformations employing traditional batch conditions. Notably, strategies based on flow chemistry, especially for amide reductions, are much less explored. Herein, a simple process was developed in which neat borane dimethylsulfide complex (BH3 ⋅DMS) was used to reduce various esters and amides under continuous-flow conditions
Sulfinamide Phosphinates as Chiral Catalysts for the Enantioselective Organocatalytic Reduction of Imines
作者:Ahmed Chelouan、Rocío Recio、Lorenzo G. Borrego、Eleuterio Álvarez、Noureddine Khiar、Inmaculada Fernández
DOI:10.1021/acs.orglett.6b01509
日期:2016.7.1
A new type of chiral sulfinamide phosphinate catalysts with up to three stereogenic centers, readily accessible from commercially available starting materials, is reported. The naphthyl derivative SulPhos proved to be highly efficient in the organocatalytic asymmetric iminereduction, leading to a wide range of arylmethylamines in high yields with up to 99% ee under 10% catalyst loading. The synthetic
Enantioselective Synthesis of Primary 1-(Aryl)alkylamines by Nucleophilic 1,2-Addition of Organolithium Reagents to Hydroxyoxime Ethers and Application to Asymmetric Synthesis of G-Protein-Coupled Receptor Ligands
previously used as an efficient chiral auxiliary for the synthesis of natural products in this laboratory. The synthetic utility of this methodology involving diastereoselective methyl addition was demonstrated by further application to the asymmetric synthesis of a new type of calcium receptor agonist (calcimimetics), (R)-(+)-NPS R-568 and its thio analogue. Furthermore, diastereoselective vinylation was accomplished
Nucleophilic addition of methyllithium to chiral oxime ethers: asymmetric preparation of 1-(aryl)ethylamines and application to a synthesis of calcimimetics (+)-NPS R-568 and its thio analogue
Chiral (E)-arylaldehyde oxime ethers, prepared using (R)-1-phenyl-1,2-ethanediol as a chiral auxiliary, undergo nucleophilic addition with methyllithium to give diastereomerically enriched O-alkyl hydroxylamines which, after reductive NO bond cleavage, lead to the corresponding (R)-1-(aryl)ethylamines. This methodology has been applied to the enantioselective synthesis of a new type of arylalkylamine
Chemoenzymatic synthesis of the calcimimetics (+)-NPS R-568 via asymmetric reductive acylation of ketoxime intermediate
作者:Kiwon Han、Yunwoong Kim、Jaiwook Park、Mahn-Joo Kim
DOI:10.1016/j.tetlet.2010.04.121
日期:2010.7
A practical and efficient procedure for the synthesis of a potent calcimimetic (+)-NPS R-568 was developed. This procedure includes as the key step the asymmetric reductiveacylation of a ketoxime intermediate catalyzed by a Pd nanocatalyst and a lipase in combination. The target compound was prepared from commercially available 3′-methoxyacetophenone via five steps in overall 63% yield.