نتایج جستجو برای: chiral pyrrolidines
تعداد نتایج: 37647 فیلتر نتایج به سال:
This thesis deals with the development of synthetic methodologies for the preparation of enantioand diastereomerically enriched nitrogen-containing heterocycles. Asymmetric Lewis acid mediated Diels-Alder reactions with 2H-azirines as dienophiles have been studied. Diastereoselective reactions with enantiomerically pure auxiliary-derived 2H-azirines afforded substituted biand tri-cyclic azahete...
The synthesis of a small library of dihydrouracils spiro-fused to pyrrolidines is described. These compounds are synthesized from beta-aryl pyrrolidines, providing products with the 2-arylethyl amine moiety, a structural feature often encountered in compounds active in the central nervous system. The b-aryl pyrrolidines are synthesized through a three-step methodology that includes a Knoevenage...
The stereoselective synthesis of trisubstituted 2-trifluoromethyl pyrrolidines by asymmetric Michael addition/hydrogenative cyclization is described. The direct organocatalytic addition of 1,1,1-trifluoromethylketones to nitroolefins proceeds under mild reaction conditions and low catalyst loadings to provide Michael adducts in high yield with excellent diastereo- and enantioselectivity. Cataly...
The functionalization of olefins induced by chiral hypervalent iodine reagents is a basic method for obtaining enantiomerically enriched molecules and biologically active natural products. It one the new promising fields in asymmetric synthesis. Throughout past 20 years development this area, on hand, stereoselective functionalizations alkenes such as disulfonyloxylation, diacetoxylation, dihal...
Although great success has been achieved in asymmetric fluoroalkylation reactions via nucleophilic or electrophilic processes, the development of asymmetric radical versions of this type of reactions remains a formidable challenge because of the involvement of highly reactive radical species. Here we report a catalytic asymmetric radical aminoperfluoroalkylation and aminodifluoromethylation of ...
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