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Statins are inhibitors of 3‐hydroxy‐3‐methyl‐glutaryl coenzyme A reductase (HMG‐CoA reductase) and became the standard of care for treatment of hypercholesterolemia because of their efficacy, safety, and long‐term benefits. They are administered as diastereo‐ and enantiomerically pure compounds. We summarize here two new approaches for the total synthesis of the most important representatives, atorvastatin,...
Practical, cheap, and stereoselective synthetic methods were applied to the preparation of novel 1‐(aminoalkyl)naphthol and γ‐aminoalcohol tridentate ligands. The ligands obtained were conveniently applied with good results as catalytic sources in the borane‐mediated enantioselective reduction of acetophenone with borane dimethylsulfide. Conformational analysis through molecular modeling allows the...
Two new chiral dinuclear Mn(III)‐Salen complexes with inherent phase‐transfer capability have been synthesized, which serve as catalysts in the asymmetric epoxidation of nonfunctionalized alkenes. Experimental results show these complexes are effective catalysts for the asymmetric epoxidation of some cyclic alkenes and the catalysts have certain inherent phase‐transfer capability during the epoxidation...
Enantioselective reductions are a key to successful target‐oriented syntheses. Finding the most suitable conditions is often a tedious work that is especially hampered by the time‐consuming analytical investigation. A possible solution is the combined use of high‐performance liquid chromatography and circular dichroism to find a suitable system for providing enantiomerically pure alcohols. This investigation...
Nitroso compounds have two reactive nitrogen and oxygen atoms. It is interesting and important to perform a nitrogen or oxygen selective reaction with interesting substrates. These atom specific reactions are crucial to specifically synthesis of specific compounds. An enantioselective N‐specific reaction of nitrosobenzene with unmodified aldehydes was successfully achieved catalyzed first by a variety...
Asymmetric bis(hydroxyamide)‐based zinc‐chelate catalysts are able to promote the enantioselective addition of diethylzinc to benzaldehyde in the absence of titanium with yields and ees comparable, or inclusively superior, to their C2‐symmetric analogues. This unexpected fact demonstrates that the previously established assumption on the necessity of using C2‐symmetric bis(hydrdoxyamides) to generate...
Three alkyltitanium reagents of RTi(O‐i‐Pr)3 (R = Cy (1a), i‐Bu (1b), and n‐Bu (1c)) were prepared in good yields. The high‐resolution mass spectroscopy showed that 1b and 1c in the gas phase are monomeric species. However, the solid state of 1a revealed a dimeric structure. Asymmetric additions of 1a, 1b, 1c to aldehydes catalyzed by a titanium catalyst of (R)‐H8‐BINOL were studied at room temperature...
The screening of the catalytic activity in the diethylzinc reaction of a series of easily accessible (1S)‐ketopinic‐acid derived hydroxyamides, designed by key structure modifications of a parent highly active related bis(hydroxyamide), has allowed to find the first case of dual stereoselection in highly structurally close ligands of such interesting chemically sustainable typology. The found striking...
Several pyrrolidine–camphor derived organocatalysts were designed and synthesized. These organocatalysts were used for direct Michael reaction of aldehydes with nitroalkenes to give the desired γ‐nitrocarbonyl compounds in high yields (up to 99%), high diastereoselectivities (syn:anti up to 92:8), and good to excellent enantioselectivities (up to 94% ee). Possible transition‐state model was also proposed...
This article describes a copper‐catalyzed aza‐Henry reaction. Copper complexes of camphor‐derived aminopyridines catalyze the addition of nitromethane to N‐(2‐pyridyl)sulfonyl aldimines to give the corresponding β‐nitrosulfonamides with good yields and variable enantiomeric excesses (up to 83%). An example of transformation of these compounds into N‐(2‐pyridyl)sulfonyl‐α‐amino acids and deprotection...
A series of new camphorsulfonylated ligands derived from chiral 2‐amino‐2′‐hydroxy‐1,1′‐binaphthyl (NOBIN) and (+)‐camphorsulfonic acid were synthesized by a short and simple synthetic sequence, and their enantioselective catalytic activities were assessed in the nucleophilic addition reaction of dialkylzinc reagents to aldehydes in the presence of titanium tetraisopropoxide. The most efficient ligand,...
Polystyrene grafted with a chiral zinc‐complexing camphor‐derived N,N‐disubstituted hydroxyamide is proposed as a new type of functional polymer of high reusability for the development of sustainable organozinc‐catalyzed asymmetric reactions. The main goal of this new functional polymer is the ease of the hydroxyamide‐moiety preparation (cheap chiral ligand obtained straightforwardly from an enantiopure...
cis‐(3R)‐(9‐anthryl) derivative of cyclohexanol was conveniently obtained in enantiomerically pure form from 2‐cyclohexenone using asymmetric Michael addition of anthrone catalyzed by l‐proline in a key step. The absolute configuration of the addition product was unequivocally determined by means of electronic circular dichroism measurements combined with calculation of the circular dichroism spectrum...
Dirhodium metallopeptides have been developed as selective catalysts for asymmetric cyclopropanation reactions. A selective ligand sequence has been identified by screening on‐bead metallopeptide libraries in a 96‐well plate format. Efficient ligand synthesis and screening allows a 200‐member library to be created and assayed in less than three weeks. These metallopeptides catalyze efficient cyclopropanation...
On‐column reaction gas chromatography combines the power of separation and rapid analysis of reactants and reaction products with screening of reactions in a single step. Not only conversions but the reaction rates at various temperatures can be obtained from single measurements, making this approach superior to the time‐consuming measurements typically performed in reaction progress analysis. However,...
The stereoselective bromofunctionalization of alkenes, particularly the enantioselective format, has been a subject of intense research in recent years. The ground‐breaking works are documented in recent reviews. On the other hand, this account will provide an insight into our group's approach in tackling the challenges in enantioselective bromocyclization of alkenes as well as the development of...
Efficient synthesis of several new atropisomeric amino alcohols having 1‐phenyl‐1H‐pyrrole skeleton are reported. Steric arrangements of the products were confirmed by a single‐crystal X‐ray measurement. The consequences of the size of the N‐substituents on enantioinduction were examined by employing the enantioselectivecatalytic addition of diethylzinc to a series of substituted benzaldehydes (yields...
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