Unprecedented Asymmetric Induction Through Configurationally Stable Lithium N-(α-Methylbenzyl)phosphinamides. A New Entry to Enantiomerically Pure γ-Aminophosphinic Acids and Esters.

ChemInform ◽  
2006 ◽  
Vol 37 (12) ◽  
Author(s):  
Ignacio Fernandez ◽  
Gloria Ruiz Gomez ◽  
Ignacio Alfonso ◽  
Maria J. Iglesias ◽  
Fernando Lopez Ortiz
Keyword(s):  
Asymmetric Induction ◽  
Enantiomerically Pure ◽  
New Entry

P-Chiral 2-{1'-[Butyl(phenyl)phosphanyl]ferrocen-1-yl}-4-isopropyl-4,5-dihydrooxazoles: A Second Chirality Center in Catalytic System

2005 ◽  
Vol 70 (3) ◽  
pp. 361-369 ◽  
Author(s):  
Dušan Drahoňovský ◽  
Petr Štěpnička ◽  
Dalimil Dvořák
Keyword(s):  
Catalytic System ◽  
Asymmetric Induction ◽  
Dimethyl Malonate ◽  
Enantiomerically Pure

P-Chiral (S,RP)-2-{1'-[butyl(phenyl)phosphanyl]ferrocen-1-yl}-4-isopropyl-4,5-dihydrooxazole (6) and (S,SP)-2-{1'-[butyl(phenyl)phosphanyl]ferrocen-1-yl}-4-isopropyl-4,5-dihydrooxazole (7) were prepared by the procedure developed by Jugé, starting from enantiomerically pure (-)- or (+)-ephedrine and dichloro(phenyl)phosphine. Compounds 6 and 7 were examined for asymmetric induction in the Pd-catalyzed reaction of rac-1,3-diphenylallyl acetate with dimethyl malonate. The best results were obtained with 7 (98% ee), while 6 gave 82% ee.

scholarly journals Catalytic Enantioselective Pyridine N-Oxidation

2019 ◽  
Author(s):  
Sheng-Ying Hsieh ◽  
Yu Tang ◽  
Simone Crotti ◽  
Elizabeth Stone ◽  
Scott Miller
Keyword(s):  
Aspartic Acid ◽  
Free Acid ◽  
Catalytic Cycle ◽  
Asymmetric Induction ◽  
Side Chain ◽  
Substituted Pyridines ◽  
Stereogenic Center ◽  
New Entry

The catalytic, enantioselective N-oxidation of substituted pyridines is described. The approach is predicated on a biomolecule-inspired catalytic cycle wherein high levels of asymmetric induction are provided by aspartic acid containing peptides as the aspartyl side chain shuttles between free acid and peracid forms. Desymmetrizations of bis(pyridine) substrates bearing a remote pro stereogenic center are demonstrated, presenting a new entry into chiral pyridine frameworks in a heterocycle-rich molecular environment. Representative functionalizations of the enantioenriched pyridine N-oxides further document the utility of this approach. Demonstration of the asymmetric N-oxidation in two venerable drug-like scaffolds, Loratadine and Varenicline, show the likely generality of the method for highly variable and distinct chiral environments, while also revealing that the approach is applicable to both pyridines and 1,4-pyrazines. <br><br>

Recent progress in asymmetric synthesis of aminophosphonic acids mediated by chiral sulfinyl auxiliary

2017 ◽  
Vol 89 (3) ◽  
pp. 357-365 ◽  
Author(s):  
Marian Mikołajczyk ◽  
Piotr Łyżwa
Keyword(s):  
Asymmetric Synthesis ◽  
Recent Progress ◽  
Asymmetric Induction ◽  
Enantiomerically Pure ◽  
Aminophosphonic Acids

AbstractThis account outlines the recent results on our strategy of the diastereoselective asymmetric synthesis of aminophosphonic acids (APs) using enantiomeric sulfinimines as chirality inducing reagents. Three important topics are discussed: (a) application of a double asymmetric induction in the synthesis of enantiomerically pure APs; (b) development of a general approach to the synthesis of γ-aminophosphonic acids (γ-APs) and (c) the use enantiomeric N-(p-tolylsulfinyl)cinnamaldimines in the synthesis of diverse α- and β-aminophosphonic acids (AP3, AP4) including the first synthesis of (R)-phosphoemeriamine.

Modification of the Atropisomeric N,N-Ligand 2,2'-Di(pyridin-2-yl)-1,1'-binaphthalene and Its Application to the Asymmetric Allylation of Benzaldehyde

2003 ◽  
Vol 68 (5) ◽  
pp. 865-884 ◽  
Author(s):  
Jonathan P. H. Charmant ◽  
Neil J. Hunt ◽  
Guy C. Lloyd-Jones ◽  
Thorsten Nowak
Keyword(s):  
Asymmetric Catalysis ◽  
Pyridine Ring ◽  
Parent Compound ◽  
Cross Coupling ◽  
Asymmetric Induction ◽  
Asymmetric Allylation ◽  
Enantiomerically Pure ◽  
Negative Effect

The atropisomeric compound 2,2'-di(pyridin-2-yl)-1,1'-binaphthalene (1) has been chlorinated, via its bis-N-oxide 2, at the 4 and 6 pyridine ring positions so as to generate the three isomeric species: 2,2'-bis(6-chloropyridin-2-yl)- (3a), 2-(4-chloropyridin-2-yl)-2'-(6-chloropyridin-2-yl)- (3b) and 2,2'-bis(4-chloropyridin-2-yl)-1,1'-binaphthalene (3c). The dichlorinated compounds underwent Ni-catalysed Kumada cross-coupling with MeMgI to give the methylated pyridine isomers: 2,2'-bis(6-methylpyridin-2-yl)- (4a), 2-(4-methylpyridin-2-yl)-2'-(6-methylpyridin-2-yl)- (4b) and 2,2'-bis(4-methylpyridin-2-yl)-1,1'-binaphthalene (4c). The enantiomerically pure forms of the six novel ligands (3a-3c and 4a-4c), prepared from enantiomerically pure 2,2'-di(pyridin-2-yl)-1,1'-binaphthalene (1), were tested in asymmetric catalysis, but proved to be no better and in most cases poorer than parent 1. The coordination of the ligands to Zn and Pd fragments has been explored and compared with the parent compound 1 so as to rationalise the negative effect of pyridine substitution on asymmetric induction in the zinc-catalysed allylation of benzaldehyde.

scholarly journals Catalytic Enantioselective Pyridine N-Oxidation

2019 ◽  
Author(s):  
Sheng-Ying Hsieh ◽  
Yu Tang ◽  
Simone Crotti ◽  
Elizabeth Stone ◽  
Scott Miller
Keyword(s):  
Aspartic Acid ◽  
Free Acid ◽  
Catalytic Cycle ◽  
Asymmetric Induction ◽  
Side Chain ◽  
Substituted Pyridines ◽  
Stereogenic Center ◽  
New Entry

The catalytic, enantioselective N-oxidation of substituted pyridines is described. The approach is predicated on a biomolecule-inspired catalytic cycle wherein high levels of asymmetric induction are provided by aspartic acid containing peptides as the aspartyl side chain shuttles between free acid and peracid forms. Desymmetrizations of bis(pyridine) substrates bearing a remote pro stereogenic center are demonstrated, presenting a new entry into chiral pyridine frameworks in a heterocycle-rich molecular environment. Representative functionalizations of the enantioenriched pyridine N-oxides further document the utility of this approach. Demonstration of the asymmetric N-oxidation in two venerable drug-like scaffolds, Loratadine and Varenicline, show the likely generality of the method for highly variable and distinct chiral environments, while also revealing that the approach is applicable to both pyridines and 1,4-pyrazines. <br><br>

Complete asymmetric induction in synthesis of enantiomerically pure steroid intermediates of natural configuration

1981 ◽  
Vol 46 (25) ◽  
pp. 5244-5246 ◽  
Author(s):  
Gary H. Posner ◽  
Martin Hulce ◽  
John P. Mallamo ◽  
Steven A. Drexler ◽  
Jon Clardy
Keyword(s):  
Asymmetric Induction ◽  
Enantiomerically Pure ◽  
Natural Configuration
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