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.

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 Organocatalytic Michael Addition to (D)-Mannitol-Derived Enantiopure Nitroalkenes: A Valuable Strategy for the Synthesis of Densely Functionalized Chiral Molecules

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4588 ◽  
Author(s):  
Lucia Caruso ◽  
Alessandra Puglisi ◽  
Emmerance Gillon ◽  
Maurizio Benaglia
Keyword(s):  
Michael Addition ◽  
Renewable Resources ◽  
Large Scale ◽  
Chiral Molecules ◽  
Flow Conditions ◽  
Dimethyl Malonate ◽  
Enantiomerically Pure ◽  
Keto Esters ◽  
Bicyclic Lactams ◽  
High Stereoselectivity

Carbohydrates are abundant renewable resources and are a feedstock for green chemistry and sustainable synthesis of the future. Among the hexoses and the pentoses present in biomass, mannitol was selected in the present project as a valuable platform, directly available from the chiral pool, to build highly functionalized molecules. Starting from (R)-2,3-O-cyclohexylidene glyceraldehyde, which is easily prepared in a large scale from D-mannitol, an enantiopure chiral nitro alkene was prepared by reaction with nitromethane, and its reactivity studied. Organocatalytic Michael addition of dimethyl malonate, β-keto esters, and other nucleophiles on the nitro alkene afforded high stereoselectivity and densely functionalized chiral molecules, which were further synthetically developed, leading to five-membered lactones and bicyclic lactams. Preliminary studies showed that the metal-free catalytic reaction on the chiral nitro alkene can be performed under continuous flow conditions, thus enabling the use of (micro)mesofluidic systems for the preparation of enantiomerically pure organic molecules from the chiral pool.

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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