نتایج جستجو برای: functionalized piperidines
تعداد نتایج: 21966 فیلتر نتایج به سال:
A convenient synthetic route for the synthesis of biologically active functionalized piperidines usingZn(OAc)2.2H2O as a highly efficient catalyst via five-component reaction of aromatic aldehydes,anilines and β-ketoesters at ambient temperature has studied. Mild reaction conditions, simplicity ofoperation and work-up procedures with no necessity of chromatographic purification steps, theavaila...
Reductive aminases (RedAms) have recently emerged as promising biocatalysts for the synthesis of chiral secondary amines by coupling primary with aldehydes/ketones. However, access to tertiary remains more problematic, particularly when ketones amines. Here we show that scope these enzymes can be extended allow selective reductive aminations cyclic amines, such piperidines and morpholines, both...
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...
Previously, we reported an efficient asymmetric synthesis of substituted piperidines through an exocyclic chirality induced nitroalkene/amine/enone (NAE) condensation reaction. An effective protecting group strategy was developed herein to achieve enantiopure piperidines (yields up to 92%) with complete chirality retention (ee > 95%). A simple derivatization of the obtained piperidines gave thi...
Chiral aminoalkyl epoxyaziridine 1 is synthesized in high yield and diastereoselectivity from L-serine. Ring opening of epoxyaziridine 1 with primary amines is carried out with total chemo- and regioselectivity, affording chiral polyfunctionalized piperidines 8. The structure of these trisubstituted piperidines is established by NMR studies.
Iridium-catalyzed asymmetric hydrogenation of N-alkyl-2-alkylpyridinium salts provided 2-aryl-substituted piperidines with high levels of enantioselectivity. Simple benzyl and other alkyl groups successfully activated the challenging pyridine substrates toward hydrogenation. The use of the unusual chiral-phosphole-based MP(2) -SEGPHOS was the key to the success of this approach which provides a...
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