نتایج جستجو برای: aldoxime
تعداد نتایج: 423 فیلتر نتایج به سال:
A Ni(0)-catalyzed Tishchenko reaction which can be applied to a variety of aliphatic aldehydes (primary, secondary, tertiary) and aromatic aldehydes was developed. The reaction might proceed via a hetero-nickelacycle intermediate.
A general efficient regioselective cobalt catalyzed carbonylation of unactivated C(sp3)-H bonds of aliphatic amides was demonstrated using atmospheric (1-2 atm) carbon monoxide as a C1 source. This straightforward approach provides access to α-spiral succinimide regioselectively in a good yield. Cobalt catalyzed sp3 C-H bond carbonylation is reported for the first time including the functionali...
The intermolecular addition of N-H bonds to unactivated alkenes remains a challenging, but desirable, strategy for the synthesis of N-alkylamines. We report the intermolecular amination of unactivated α-olefins and bicycloalkenes with arylamides and sulfonamides to generate synthetically useful protected amine products in high yield. Mechanistic studies on this rare catalytic reaction revealed ...
Under Rh(I) catalysis, α-ketoamides undergo intermolecular hydroacylation with aliphatic aldehydes. A newly designed Josiphos ligand enables access to α-acyloxyamides with high atom-economy and enantioselectivity. On the basis of mechanistic and kinetic studies, we propose a pathway in which rhodium plays a dual role in activating the aldehyde for cross-coupling. A stereochemical model is provi...
An easy hydroxylation of aliphatic nitroalkenes in high yields and enantioselectivities is catalysed by bifunctional thiourea-cinchona alkaloids giving access to optically active nitroalcohols and aminoalcohols as final products.
We describe an unprecedented cycloaddition reaction of 2-pyrones with aliphatic nitroalkenes catalyzed by a new bifunctional cinchona alkaloid-derived catalyst bearing a bulky TIPS-ether at the 9-position. The [2.2.2] bicyclic adducts were obtained in good yield with excellent diastereo- and enantioselectivity. Carbon isotope effects were measured by (13)C NMR and are indicative of a stepwise m...
An efficient protocol for the highly regioselective opening of aliphatic zirconacyclopentadienes is reported. The one-pot process involves a zirconocene-mediated cyclization of 1,6-diynes and highly selective cleavage of the metallacycles with NBS and enables a concise synthesis of the tetrahydrofuran-core of the leupyrrins.
A highly enantioselective construction of delta- and gamma-lactone[2,3-b]piperidine skeletons was accomplished by tandem aza-Diels-Alder reaction-hemiacetal formation-oxidation from N-Tos-1-aza-1,3-butadienes and aliphatic dialdehydes.
The most comprehensive nucleofugality scale, based on the correlation and solvolytic rate constants of benzhydrylium derivatives, has recently been proposed by Mayr and co-workers (Acc. Chem. Res., 2010, 43, 1537-1549). In this work, the possibility of employing quantum chemical calculations in further determination of nucleofugality (Nf) parameters of leaving groups is explored. Whereas the he...
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