Iron-catalyzed domino coupling reactions of π-systems

The development of environmentally benign, inexpensive, and earth-abundant metal catalysts is desirable from both an ecological and economic standpoint. Certainly, in the past couple decades, iron has become a key player in the development of sustainable coupling chemistry and has become an indispensable tool in organic synthesis. Over the last ten years, organic chemistry has witnessed substantial improvements in efficient synthesis because of domino reactions. These protocols are more atom-economic, produce less waste, and demand less time compared to a classical stepwise reaction. Although iron-catalyzed domino reactions require a mindset that differs from the more routine noble-metal, homogenous iron catalysis they bear the chance to enable coupling reactions that rival that of noble-metal-catalysis. This review provides an overview of iron-catalyzed domino coupling reactions of π-systems. The classifications and reactivity paradigms examined should assist readers and provide guidance for the design of novel domino reactions.

Microwave-Assisted Domino Cyclization Reactions

Background: Microwave-assisted domino cyclization reactions have attracted great interest for researchers to synthesize complex compounds in shorter times with increase yields. The domino reactions were used in various synthetic approaches and many drug deliveries in medicinal chemistry with microwave assisted approach. Methods: Microwave irradiation has been applied for the various domino reactions. The research related to microwave assisted domino cyclization was reviewed and the important methodologies are collected from 2011-2021. Results: Only those methodologies that involve microwave-assisted domino cyclization reactions during synthesis in a related manner have been reviewed. Along with some recent syntheses that are microwave-assisted regarding new heterocyclic moieties are summarized. Conclusion: Microwave-assisted domino cyclization reactions can be employed to quickly explore and increase molecular diversity in synthetic chemistry. We hope that this review will be helpful to find out complex molecule synthesis by microwave-assisted domino cyclization reactions. This review aimed to explain the applications of microwaves for the domino reactions from 2011-2021. In this respect, the microwave mediated methods help researchers to make helpful studies.

Domino Reactions of Chromones with Heterocyclic Enamines

Domino reactions of heterocyclic enamines with chromone derivatives provides a convenient synthesis of a great variety of annulated heterocyclic ring systems. The course of the reaction depends on the type of substituent located at position 3 of the chromone. Reactions of 3-unsubstituted chromones, 3-nitrochromones, and 3-halochromones proceed by conjugate addition of the carbon atom of the enamine to carbon C-2 of the chromone, ring cleavage, and recyclization via the chromone carbonyl group. In the case of 3-formylchromes, 3-dichloroacetylchromone, 3-perfluoroalkanoylthiochromones, 3-(2-fluorobenzoyl)chromones, and 3-methoxalylchromones the final cyclization proceeds via the carbonyl group located outside the chromone moiety. The functional groups located at the carbonyl group at position 3 of the chromone allow for further synthetic transformations including additional ring closures.Contents1 Introduction2 3-Unsubstituted Chromones3 3-Nitrochromones4 3-Formylchromes5 3-Dichloroacetylchromone6 3-Perfluoroalkanoylthiochromones7 3-Methoxalylchromones8 3-(2-Fluorobenzoyl)chromones9 3-Halochromones10 Chromone-3-carboxylic Acids11 Conclusions

Synthesis of Diethoxy Arylphosphoryl Functionalyzed Fully Substituted 5‑Triazenyl-1,2,3-triazoles via Chelation-Assisted Interrupted Domino Reactions of Ortho-Azidophosphonates with Copper(I) Alkynes

We describe the synthesis of 1,4-(disubstituted)-5-triazenyl-1,2,3-triazoles bearing diethoxy arylphosphoryl moieties via a domino reaction between ortho-azidophosphonates and premade copper(I) alkynydes involving a chelation-assisted [3+2] cycloaddition followed by interception of the copper(I) triazolide generated by the azide. The resulting dicopper(I) triazoletriazenide complex has been characterized through X-ray diffraction.

Synthesis of biologically active heterocycles by domino reactions with SN2/Thorpe-Ziegler reaction step.

The review includes methods for the synthesis of five- and six-membered heterocycles and their annulated analogs. These methods are based on anionic domino reactions, which have a common step - SN2/Thorpe-Ziegler reaction. Data on the biological activity of these heterocycles are summarized.