Catalytic dehydrogenative cross-coupling: forming carbon-carbon bonds by oxidizing two carbon-hydrogen bonds

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.

The coupling of aryl or vinyl halides with terminal acetylenes catalysed by palladium and other transition metals, commonly termed as Sonogashira cross-coupling reaction, is one of the most important and widely used sp2–sp carbon–carbon bond formation reactions in organic synthesis, frequently employed in the synthesis of natural products, biologically active molecules, heterocycles, molecular electronics, dendrimers and conjugated polymers or nanostructures. This critical review focuses on developments in the Sonogashira reaction achieved in recent years concerning catalysts, reaction conditions and substrates (352 references).

Recent advances in Sonogashira reactions

5.4. Miscellaneous Examples 2295 5.4.1. Couplings with Other Catalysts 2295 5.4.2. The Use of Other Boron Reagents 2295 5.4.3. Related Coupling Reactions 2296 5.5. Summary 2297 6. Sonogashira Coupling 2297 6.1. Couplings with Pd Particles 2297 6.2. Studies with Immobilized Palladium Complexes 2299 6.3. Miscellaneous Examples 2301 6.4. Carbonylative Sonogashira Couplings 2302 6.5. Summary 2302 7. Stille Couplings 2302 7.1. Stille Coupling 2302 7.2. Carbonylative Stille Coupling 2304 7.3. Summary 2304 8. Miscellaneous Cross-Coupling Reactions 2304 9. Allylations 2305 9.1. Tsuji-Trost Allylation 2305 9.2. Allylation of Boron Reagents 2306 10. Homocouplings 2307 10.1. Summary 2308 11. C-C Couplings in Continuous Systems 2308 12. Conclusions and Outlook 2311 Author Information 2314 Biography 2314 References 2314

Efficient, selective, and recyclable palladium catalysts in carbon-carbon coupling reactions.

A review. Transition metal catalyzed decarboxylative allylations, benzylations, and interceptive allylations are reviewed.

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Transition Metal-Catalyzed Decarboxylative Allylation and Benzylation Reactions

An efficient and reusable Cu2O/PPh3/TBAB (n-Bu4NBr) system for the cross-coupling reactions of aryl and heteroaryl halides with terminal alkynes has been developed. Four types of Cu2O, including bulky Cu2O, cubic Cu2O nanoparticles, octahedral Cu2O nanoparticles, and spherical Cu2O nanoparticles, were examined, and the octahedral Cu2O nanoparticles were found to be the most effective catalyst for the reaction. In the presence of the octahedral Cu2O nanoparticles, PPh3, and TBAB, a variety of aryl and heteroaryl halides were reacted with alkynes including alkynols smoothly in moderate to good yields. Noteworthy is that the Cu2O/PPh3/TBAB system can be recovered and reused several times without loss of any activities.

Reusable Cu2O/PPh3/TBAB system for the cross-couplings of aryl halides and heteroaryl halides with terminal alkynes

Selective synthesis of spiro[4,5]trienyl acetates via an intramolecular electrophilic ipso-iodocyclization process.

A novel electrophilic ipso-cyclization involving an electrophile-exchange process has been developed. In the presence of CuX (X = I, Br, SCN) and electrophilic fluoride reagents, a variety of N-(p-methoxyaryl)propiolamides and 4-methoxyphenyl 3-phenylpropiolate were cyclized to selectively afford the corresponding spiro[4.5]decenones in moderate to good yields. It is noteworthy that two azaquaternary tricyclic products were synthesized through a two-step pathway involving an electrophilic ipso-cyclization and then an intramolecular Heck reaction.

Electrophilic ipso-cyclization of N-(p-methoxyaryl)propiolamides involving an electrophile-exchange process.

A combination of Cu2O nanoparticles with P(o-tol)3 shows highly catalytic activity for the Stille cross-coupling reaction. A series of copper catalysts and ligands were evaluated, and Cu2O nanoparticles combined with P(o-tol)3 provided the best results. In the presence of Cu2O nanoparticles and P(o-tol)3, a variety of aryl halides including aryl chlorides underwent the Stille reaction with organotins smoothly in moderate to excellent yields using inexpensive TBAB (n-Bu4NBr) as the medium. It is noteworthy that the Cu2O/P(o-tol)3/TBAB system can be recovered and reused at least three times without any loss of catalytic activity among the reactions of aryl iodides and activated aryl bromides.

Reusable copper-catalyzed cross-coupling reactions of aryl halides with organotins in inexpensive ionic liquids.

A new, general method for the synthesis of spiro[4,5]trienones is described by the intramolecular ipso-halocyclization of 4-(p-unsubstituted-aryl)-1-alkynes. In the presence of halide electrophiles, a variety of 4-(p-unsubstituted-aryl)-1-alkynes underwent the intramolecular ipso-halocyclization with water smoothly, affording the corresponding halo-substituted spiro[4,5]trienones in moderate to good yields. The obtained spiro[4,5]trienones can be applied in constructing the azaquaternary tricyclic skeleton via Pd-catalyzed Heck reaction. Notably, the prepared spiro[4,5]trienones and azaquaternary tricycles are of importance in the areas of pharmaceuticals and agrochemicals. The mechanism of the intramolecular ipso-halocyclization reaction is also discussed according to the 18O-labeling experiments and DFT calculations.

Intramolecular ipso-Halocyclization of 4-(p-Unsubstituted-aryl)-1-alkynes Leading to Spiro[4,5]trienones: Scope, Application, and Mechanistic Investigations

Bo-Xiao Tang

Papers

Reusable Cu2O/PPh3/TBAB system for the cross-couplings of aryl halides and heteroaryl halides with terminal alkynes

Selective synthesis of spiro[4,5]trienyl acetates via an intramolecular electrophilic ipso-iodocyclization process.

Electrophilic ipso-cyclization of N-(p-methoxyaryl)propiolamides involving an electrophile-exchange process.

Reusable copper-catalyzed cross-coupling reactions of aryl halides with organotins in inexpensive ionic liquids.

Intramolecular ipso-Halocyclization of 4-(p-Unsubstituted-aryl)-1-alkynes Leading to Spiro[4,5]trienones: Scope, Application, and Mechanistic Investigations