6.4. Polyynes 3123 6.5. Using R-Hydroxy Stannanes 3124 6.6. Using the Hurtley Reaction 3124 6.7. Using a Methylenation Reaction 3125 7. Conclusions and Future Prospects 3125 8. Uncommon Abbreviations 3125 9. Acknowledgments 3125 10. Note Added in Proof 3125 11. References 3126 * Authorstowhomcorrespondenceshouldbeaddressed(evano@chimie.uvsq.fr, nicolas.blanchard@uha.fr). † Université de Versailles Saint Quentin en Yvelines. ‡ Université de Haute-Alsace. Chem. Rev. 2008, 108, 3054–3131 3054

Copper-mediated coupling reactions and their applications in natural products and designed biomolecules synthesis.

https://www.chem.ccu.edu.tw/~joyce/referance/ericyang/Coord.%20Chem.%20Rev/Coord.%20Chem.%20Rev.%202004,%20248,%202337-2364.pdf

Copper in cross-coupling reactions: The post-Ullmann chemistry

An Overview on Ynamines
Alkynes represent one of the most important and versatile building blocks in organic synthesis. Heteroatom-substituted alkynes, which can be considered as subgroups of alkynes, have also been vastly utilized in developing synthetic methods. In particular, ynamines [1-amino-alkynes or N-alkynyl amines] became the most valuable subgroup of alkynes after the establishment of their practical synthesis in the 1960's. The first attempt at preparation of an ynamine was reported by Bode1,2 in 1892. While well-characterized ynamines were reported in 19583 and 1960,4 a practical synthesis was not achieved until the effort led by Viehe5 in 1963 in addition to other subsequent works. In the ensuing twenty years, the synthetic significance of ynamines in organic and organometallic chemistry was firmly established by the work of many creative synthetic chemists. These elegant pioneer works have been informatively and carefully reviewed by Viehe in 19676 and 1969;7 Ficini in 1976;8 Pitacco and Valentin9 in 1979; Collard-Motte and Janousek10 in 1986; Himbert11 in 1993; and most recently by us12,13 and Katritzky14.





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The synthetic eminence of ynamines is well merited because of the predicable regioselectivity in their transformations as shown by the generalization in Scheme i, and more importantly, because they are inherently highly reactive. However, this latter attribute is also the source of the limitation that has seriously hampered the development of ynamine chemistry, thereby shortening the period of its prominence in synthesis. Ynamines are very sensitive toward hydrolysis, as protonation of the electron-rich alkynyl motif affords reactive keteniminium intermediates, which upon trapping with water leads to simple amides in a rather expensive manner (Scheme i). This hydrolytic instability has caused much difficulty in the experimental preparation and general handling of ynamines, and more detrimentally, rendered ynamine chemistry inaccessible.




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Scheme i



Consequently, the synthetic utility of ynamines has suffered a dramatic decline during the last thirty years.15 The most glaring limitations have been in the development of intramolecular and stereoselective reactions.7–14 The only reported intramolecular reaction of ynamines was Genet and Kahn's acid catalyzed addition of a hydroxyl group to an ynamine [i→ii in Scheme ii] in 1980,16 and although clever, it constitutes a hydrolytic process.






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Scheme ii



Besides Reinhoudt's17 sole account in 1987 reporting hetero-[4 + 2] cycloadditions of chiral ynamine iii with nitroalkenes that led to cycloadducts iv in modest de, the only other notable studies were reported ten years later by Fischer18 showcasing [2 + 2] cycloadditions of chiral ynamides v and vi with vinylidene chromium carbene complexes, and another three years later by Pericas19 in their Pauson-Khand cycloadditions using chiral ynamines vii.

Ynamides: A Modern Functional Group For The New Millennium

Ynamides display an exceptionally fine balance between stability and reactivity. They also offer unique and multiple opportunities for the inclusion of nitrogen-based functionalities into organic molecules, and are emerging as especially useful and versatile building blocks for organic synthesis. Recent breakthroughs in the preparation of these substrates have revitalized interest in nitrogen-substituted alkynes, and the beginning of the 21st century has witnessed an ever-increasing number of publications reporting the development of new reactions or synthetic sequences starting from ynamides. This Review highlights major developments in this area.

Ynamides: versatile tools in organic synthesis.

The utility of copper-mediated cross-coupling reactions has been significantly increased by the development of mild reaction conditions and the ability to employ catalytic amounts of copper. The use of diamine-based ligands has been important in these advances and in this review we discuss these systems, including the choice of reaction conditions and applications in the synthesis of pharmaceuticals, natural products and designed materials.

/pdf/diamine-ligands-in-copper-catalyzed-reactions-208l9eabhe.pdf

Diamine ligands in copper -catalyzed reactions

Copper sulfate-pentahydrate-1,10-phenanthroline catalyzed amidations of alkynyl bromides. Synthesis of heteroaromatic amine substituted ynamides.

Torquoselective 6π-Electron Electrocyclic Ring Closure of 1-Azatrienes Containing Acyclic Chirality at the C-Terminus.

A practical cross-coupling of amides with alkynyl bromides using catalytic CuSO4·5H2O and 1,10-phenanthroline is described here. This catalytic protocol is more environmentally friendly than the use of CuCN or copper halides and provides a general entry for syntheses of ynamides including various new sulfonyl and heteroaromatic amine substituted ynamides. Given the interest in ynamides, this N-alkynylation of amides should be significant for the future of ynamides in organic synthesis.

Eymi L. Vera

Papers

Copper sulfate-pentahydrate-1,10-phenanthroline catalyzed amidations of alkynyl bromides. Synthesis of heteroaromatic amine substituted ynamides.

Torquoselective 6π-Electron Electrocyclic Ring Closure of 1-Azatrienes Containing Acyclic Chirality at the C-Terminus.

Copper Sulfate-Pentahydrate-1,10-phenanthroline Catalyzed Amidations of Alkynyl Bromides. Synthesis of Heteroaromatic Amine Substituted Ynamides.