Direct Synthesis of Functional Azaxanthones by Using a Domino Three-Component Reaction

NH aldimines, generated in situ from the corresponding aldehydes by reaction with ammonium acetate, serve as nitrogen nucleophiles in reactions with 3-(1-alkynyl)chromones and 3-cyanochromones that generate functionalized azaxanthones. These processes take place under mild conditions that do not require dry solvents. The products of the reactions described represent new chemical entities. We believe that the newly developed cascade process will serve as a potent method for the synthesis of N-heterocycles and in diversity-oriented synthesis

Direct Synthesis of Functional Azaxanthones by Using a Domino Three-Component Reaction

NH aldimines, generated in situ from the corresponding aldehydes by reaction with ammonium acetate, serve as nitrogen nucleophiles in reactions with 3-(1-alkynyl)chromones and 3-cyanochromones that generate functionalized azaxanthones. These processes take place under mild conditions that do not require dry solvents. The products of the reactions described represent new chemical entities. We believe that the newly developed cascade process will serve as a potent method for the synthesis of N-heterocycles and in diversity-oriented synthesis

Direct Synthesis of Functional Azaxanthones by Using a Domino Three-Component Reaction

NH aldimines, generated in situ from the corresponding aldehydes by reaction with ammonium acetate, serve as nitrogen nucleophiles in reactions with 3-(1-alkynyl)chromones and 3-cyanochromones that generate functionalized azaxanthones. These processes take place under mild conditions that do not require dry solvents. The products of the reactions described represent new chemical entities. We believe that the newly developed cascade process will serve as a potent method for the synthesis of N-heterocycles and in diversity-oriented synthesis

An Organic Molecule Modulated Chemoselective Cyclization of Alkynyl Nitriles Tethered to 2‑Alkyl Substituted Chromones with Multireactive Sites

A small organic molecule phenylacetonitrile promoted chemoselective cyclization of (chromen-3-yl)alkynylnitriles to generate a novel tetracyclic or tricyclic chromone scaffold has been discovered. Importantly, the phenylacetonitrile serves as an anion transfer reagent changing the normal reaction of the substrate

Phase Transfer Reagent Promoted Tandem Ring-Opening and Ring-Closing Reactions of Unique 3‑(1-Alkynyl) Chromones

A phase transfer reagent promoted tandem ring-opening and ring-closing reaction of 3-(1-alkynyl) chromones has been developed. This process remarkably generates functionalized 3-acyl-2-substituted chromones. Interestingly, when 3-(hepta-1,6-diyn-1-yl)­chromone derivatives are applied, a novel tetracyclic chromone scaffold can be obtained by a further intramolecular 4 + 2 cyclization

Synthesis of Chromeno[2,3‑<i>d</i>]imidazol-9(1<i>H</i>)‑ones via Tandem Reactions of 3‑Iodochromones with Amidines Involving Copper-Catalyzed C–H Functionalization and C–O Bond Formation

A novel six-membered heterocyclic skeleton of imidazochromone was prepared via an efficient one-pot reaction including a key step of copper-catalyzed aerobic C–H intramolecular cycloetherification. Notably, this process does not require the presence of strong para electron-withdrawing groups on the phenol component. Also, the results of this effort show that acyl phenols containing electron-rich heterocycles participate in an efficient C–H activation/C–O formation process

An Organic Molecule Modulated Chemoselective Cyclization of Alkynyl Nitriles Tethered to 2‑Alkyl Substituted Chromones with Multireactive Sites

A small organic molecule phenylacetonitrile promoted chemoselective cyclization of (chromen-3-yl)alkynylnitriles to generate a novel tetracyclic or tricyclic chromone scaffold has been discovered. Importantly, the phenylacetonitrile serves as an anion transfer reagent changing the normal reaction of the substrate

Efficient and highly selective cyclization induced by Lewis acid to generate 2-hydroxyl-α-cyclogeraniol

<p>A cyclization reaction of the hydroxyl-protected geraniol epoxide induced by the different Lewis acids to generate 2-hydroxyl-α-cyclogeraniol has been explored. Compared with the previous methods, this method enhances the production and selectivity of this reaction without the consumption of a large amount of solvent. Also, the coordination of the metal with two oxygen atoms of hydroxyl groups might be crucial for the reaction is first addressed.</p

Microwave Assisted Tandem Heck–Sonogashira Reactions of <i>N,N</i>-Di-Boc-Protected 6‑Amino-5-iodo-2-methyl Pyrimidin-4-ol in An Efficient Approach to Functionalized Pyrido[2,3‑<i>d</i>]Pyrimidines

A microwave assisted tandem Heck–Sonogashira cross-coupling reaction between 6-<i>N,N</i>-di-Boc-amino-5-iodo-2-methyl pyrimidin-4-ol and various aryl alkynyl substrates has been developed. This process generates novel 5-enynyl substituted pyrimidines, which can be transformed to novel functionalized pyrido­[2,3-<i>d</i>]­pyrimidines by way of a silver catalyzed cyclization reaction

Copper(I)-Mediated Cascade Reactions: An Efficient Approach to the Synthesis of Functionalized Benzofuro[3,2-<i>d</i>]pyrimidines

A novel cascade reaction was developed for the synthesis of diverse members of a series of benzofuro[3,2-<i>d</i>]pyrimidine derivatives. The process utilizes readily prepared 3-chlorochromenones and various commercially available amidines and their analogues as starting materials. This tandem reaction is promoted by using a simple copper(I) reagent and involves a chemoselective Michael addition–heterocyclization–intramolecular cyclization sequence