Journal ArticleDOI
Synthesis of pyrrolo- and pyrido[1,2-a]xanthene [1,9-de]azepines: a study of the azepine ring construction.
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TLDR
Pentacyclic pyrrolo- and pyrido[1,2-a]xanthene[ 1,9-de]azepines were synthesized in various oxidation states by assembling the azepine ring following two strategies: 7-endo-trig cyclization of the aryl radical derived from a gamma-methylene lactam and cyclodehydration of aldehydes.Abstract:
Pentacyclic pyrrolo- and pyrido[1,2-a]xanthene[1,9-de]azepines were synthesized in various oxidation states by assembling the azepine ring following two strategies: 7-endo-trig cyclization of the aryl radical derived from a γ-methylene lactam and cyclodehydration of aldehydes. Other strategies examined (Heck reaction and intramolecular acylation) did not afford azepines, but six-membered nitrogenated rings.read more
Citations
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Book ChapterDOI
Modern developments in aryl radical chemistry
TL;DR: Modern developments of the well-known Meerwein, Pschorr, and Gomberg-Bachmann reactions are presented along with new applications in natural product syntheses.
Journal ArticleDOI
Twofold Carbon–Carbon Bond Formation by Intra- and Intermolecular Radical Reactions of Aryl Diazonium Salts
TL;DR: A variety of novel cascade reactions can be performed when the known and well-studied radical 5- or 6-exo-cyclization of an aryl diazonium salt is conducted in the presence of alkenes and further optional scavengers.
Journal ArticleDOI
Smaller, faster, better: modular synthesis of unsymmetrical ammonium salt-tagged NHC-gold(I) complexes and their application as recyclable catalysts in water.
Katrin Belger,Norbert Krause +1 more
TL;DR: Facile access towards a small library of unsymmetrical ammonium salt-tagged N-heterocyclic carbene gold(i) complexes is described and their application as recyclable catalysts in cyclization reactions of acetylenic carboxylic acids and amides to lactones and lactams in aqueous media is demonstrated.
Journal ArticleDOI
Synthesis of 9-phenol-substituted xanthenes by cascade O-insertion/1,6-conjugate addition of benzyne with ortho-hydroxyphenyl substituted para-quinone methides
TL;DR: The cascade O-insertion/1,6 conjugate addition between benzynes and ortho-hydroxyphenyl substituted para-quinone methides has been reported, affording 9-phenol substituted xanthenes in 49%-84% yields as discussed by the authors.
Journal ArticleDOI
Synthesis of 9-Substituted Xanthenes by the Condensation of Arynes with ortho-Hydroxychalcones.
TL;DR: The reaction of o-(trimethylsilyl)aryl triflates, CsF, and o-hydroxychalcones affords a general and efficient way to prepare biologically interesting 9-substituted xanthenes.
References
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Journal ArticleDOI
Enzymes of carbohydrate metabolism in soybean nodules
TL;DR: The distribution of enzymes of carbohydrate metabolism between the cortical tissue and central infected zone of the nodules was investigated and it was found that the conversion of sucrose to organic acids may take place to a large extent in the cortex tissue of the nodsules.
Journal ArticleDOI
A novel and stereoselective synthesis of (±)-cephalotaxine and its analogue
TL;DR: Cephalotaxine (1) and its analogue (3) were stereoselectively synthesized from proline via the pyrrolobenzazepine (4) through Claisen rearrangement, cationic cyclization, and regio-and stereo-selective hydroxylation as mentioned in this paper.
Journal ArticleDOI
A Short Synthesis of Lennoxamine Using a Radical Cascade
TL;DR: A short synthesis of lennoxamine has been achieved by using a radical cascade involving aryl radical-induced 7-endo cyclization and homolytic aromatic substitution.
Journal ArticleDOI
Towards a total synthesis of (−)-cephalotaxine: construction of the BCDE-tetracyclic core
TL;DR: In this article, the BCDE-tetracyclic core of (−)-cephalotaxine has been achieved in eight steps starting from N -Boc- l -proline methyl ester.
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