منابع مشابه
Ugi Multicomponent Reaction Based Synthesis of Medium-Sized Rings
An Ugi multicomponent reaction based two-step strategy was applied to generate medium-sized rings. In the first linear expansion phase, a series of diamines reacted with cyclic anhydrides to produce different lengths of terminal synthetic amino acids as the starting material for the second phase. The Ugi-4-center 3-component reaction was utilized to construct complex medium-sized rings (8-11) b...
متن کاملA platinum-catalyzed annulation reaction leading to medium-sized rings.
A platinum-catalyzed domino process with intermediate benzopyrylium cations reaches its optimum utility in the formation of 7- and 8-membered rings. With iron(III) chloride, a tetracyclic product is isolated, derived from an oxidative transformation of a metal-carbene intermediate.
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From the overground parts of an endemic Sideritis species, S. stricta, 4 diterpenes, sideridiol (1), isosidol (2), isolinearol (3), and linearol (4); 2 flavonoid glycosides, isoscutellarein 7-O-[6′′′-O-acetyl-β-Dallopyranosyl-(1→2)]-β-D-glucopyranoside (5), and isoscutellarein 7-O-[6′′′-O-acetyl-β-D-allopyranosyl(1→2)]-6′′-O-acetyl-β-D-glucopyranoside (6); a methoxyflavone, xanthomicrol (7); an...
متن کاملAnnulation Reactions of Allenyl Esters: An Approach to Bicyclic Diones and Medium-Sized Rings
A flexible approach to construct sterically congested bicyclo-alkenedione frameworks is reported. Under the action of potassium carbonate, α-sulphonyl cycloalkanones are added to functionalized allenyl esters, leading to a lactone intermediate that is subsequently reduced to initiate an intramolecular aldol cyclization to [3.2.1], [3.3.1], and [4.3.1] bicycles. Oxidation then affords bicyclic d...
متن کاملAsymmetric synthesis of medium-sized rings by intramolecular Au(I)-catalyzed cyclopropanation.
An efficient method for the asymmetric gold(I)-catalyzed preparation of medium sized rings has been developed. The method provides 7- to 9-membered rings in excellent yield. High enantioselectivities can be achieved for 7- and 8-membered ring products employing chiral gold(I) complexes. The results provide insight into the mechanism, showing the fluxional nature of gold(I)-stabilized vinyl carb...
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ژورنال
عنوان ژورنال: Pure and Applied Chemistry
سال: 1961
ISSN: 1365-3075,0033-4545
DOI: 10.1351/pac196102030533