نتایج جستجو برای: diastereoselective synthesis
تعداد نتایج: 409824 فیلتر نتایج به سال:
A novel approach to the production of chiral 1,3-cyclohexadienals has been developed. The organocatalysed asymmetric reaction of different β-disubstituted-α,β-unsaturated aldehydes with a chiral α,β-unsaturated aldehyde in the presence of a Jørgensen-Hayashi organocatalyst provides easy and stereocontrolled access to the cyclohexadienal backbone. This method allows for the synthesis of potentia...
A highly diastereoselective and practical biomimetic total synthesis of (±)-basiliolide B has been achieved through the study of the two proposed biosynthetic pathways (O-methylation and O-acylation) for the unprecedented 7-methoxy-4,5-dihydro-3H-oxepin-2-one (C ring). The synthesis featured a cyclopropanation/ring opening strategy for establishing the stereogenic centers at C8 and C9, a biomim...
An efficient enantioselective synthetic method for the synthesis of (2R)-5-phenyl-2-alkylproline tert-butyl esters was reported. The phase-transfer catalytic alkylation of tert-butyl-5-phenyl-3,4-dihydro-2H-pyrrole-2-carboxylate in the presence of chiral quaternary ammonium catalysts gave the corresponding alkylated products (up to 97% ee). The following diastereoselective reductions afforded c...
Two complex norditerpenoids, caribenols A and B, were accessed from a common building block. Our synthesis of caribenol A features the diastereoselective formation of the seven-membered ring through a Friedel-Crafts triflation and a late-stage oxidation of a furan ring. The first synthesis of caribenol B was achieved using an intramolecular organocatalytic α-arylation. An unusual intramolecular...
A simple, efficient and highly diastereoselective one-pot three-component synthesis of functionalized 2,6-disubstituted-4-tosyloxytetrahydropyrans was performed. The synthesis features an optimized Prins cyclization in which an aromatic homoallylic alcohol, an aromatic/aliphatic aldehyde, and p-toluenesulfonic acid (catalyst and reagent) are reacted in the presence of molecular sieves (MS) 4 Å ...
Abstract Quinobenzazepines are useful in medicinal chemistry, but their synthesis is very challenging. Herein, we designed and synthesized a range of multi‐functional chalcone‐based quinolinium salts; synthetic application the rapid straightforward construction quinobenzazepines was successfully explored. A wide oxa‐bridged quinobenzazepine polycycles were afforded serendipitously through dearo...
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