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Acid-catalyzed Cyclization (acid-catalyzed + cyclization)
Selected AbstractsAcid-Catalyzed Cyclization of Epoxyallylsilanes.CHEMINFORM, Issue 9 2004An Unusual Rearrangement Cyclization Process. Abstract For Abstract see ChemInform Abstract in Full Text. [source] Concise Synthesis of 2,6-Disubstituted Morpholines by Cyclization of Epoxy AlcoholsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 13 2007Domenico Albanese Abstract A novel, straightforward and high yielding synthesis of enantiomerically pure 2,6-disubstituted morpholines was developed by acid-catalyzed cyclization of epoxy alcohols. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis of 2,6-Dioxo-1,2,3,4,5,6-hexahydroindoles by Acid- Catalyzed Cyclization of Acetal-Protected (2,4-Dioxocyclohex-1-yl)acetamides and their Transformation into 5,8,9,10-Tetrahydro-6H -indolo[2,1- a]isoquinolin-9-onesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2009Benard Juma Abstract Acetal-protected (2,4-dioxocyclohex-1-yl)acetic acids were prepared by allylation of dilithiated 1,3-cyclohexane-1,3-diones, protection of the carbonyl groups and oxidation of the alkene moiety. Their reaction with amines afforded the corresponding amides which were transformed, by acid-catalyzed cyclization, into various 2,6-dioxo-1,2,3,4,5,6-hexahydroindoles. The reaction of the latter with triflic acid resulted in the formation of novel 5,8,9,10-tetrahydro-6H -indolo[2,1- a]isoquinolin-9-ones. [source] Protecting-Group-Free Total Synthesis of Isoquinoline Alkaloids by Nickel-Catalyzed Annulation of o -Halobenzaldimine with an Alkyne as the Key StepCHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2010Rajendra Prasad Korivi Dr. Abstract An efficient short total synthesis of benzo[c]phenanthridine alkaloids including oxyavicine, oxynitidine, and oxysanguinarine is described. Thus, N -methyl- o -bromobenzaldimines 1,b,d undergo regioselective cyclization with 4-(benzo[d][1,3]dioxol-5-yl)but-3-yn-1-ol (2,b) in the presence of [Ni(cod)2] (cod=1,5-cyclooctadiene). In situ oxidation of the resultant isoquinolinium salts gives isoquinolinone derivatives 5,b,d with benzo[d][1,3]dioxol-5-yl substitution at the C3 atom and a (CH2)2OH group at the C4 atom. Later, oxidation of the alcohol group in 5,b,d to the aldehyde moiety followed by acid-catalyzed cyclization and dehydration completes the total syntheses to give oxyavicine, oxynitidine, and oxysanguinarine in 67, 65, and 60,% yields, respectively. The synthesis requires four steps from o -bromobenzaldehyde derivatives. Transformations of these alkaloids to the other alkaloids in this family are also discussed herein. [source] | ||||||||||