coupling reactions, of a myriad of substrates containing C–H bonds, highlights that
the field ought to be fully examining homogeneous, heterogeneous and quasiheterogeneous–homogeneous behaviour. Having more developed and definite tests
will aid the catalysis and synthetic chemistry community at large in this respect.
At the time of writing, it is clear that the future is a very bright one for catalytic
cross-coupling chemistry, and there are many benefits and opportunities for the
employment of heterogeneous catalyst-type species. It remains to be seen whether
such catalysts will be more broadly applied in target-orientated synthesis, such as in
complex natural product synthesis. Hydrogenation on Pd/C is a mainstream reaction
in chemical synthesis, and it is the opinion of the authors that a step-change would be
seen in the broader adoption of similar catalysts in tricky synthetic transformations
(i.e. substrates containing a plethora of functionality and stereochemical information). Of particular note is that Pd/C is a preferred catalyst used in process chemistry.
The pioneering work by Glorius et al. has highlighted that conditions can be tuned to
grant Pd/C the ability to mediate complex C–H bond functionalisations. Thus, there
are many opportunities for this fascinating field going forwards, which can additionally be exploited in the synthesis of agrochemicals, pharmaceuticals and
advanced materials.
References
1. Adrio LA, Nguyen BN, Guilera G, Livingston AG, Hii KK (2012) Speciation of Pd(OAc)2 in
ligandless Suzuki–Miyaura reactions. Cat Sci Technol 2:316–323
2. Bao Y-S, Zhang D, Jia M, Zhaorigetu B (2016) Replacing Pd(OAc)2 with supported palladium
nanoparticles in ortho-directed CDC reactions of alkylbenzenes. Green Chem 18:2072–2077
3. Bao Y-S, Wang L, Jia M, Xu A, Agula B, Baiyin M, Zhaorigetu B (2016) Heterogeneous
recyclable nano-palladium catalyzed amidation of esters using formamides as amine sources.
Green Chem 18:3808–3814
4. Bedford RB, Bowen JG, Davidson RB, Haddow MF, Seymour-Julen AE, Sparkes HA,
Webster RL (2015) Facile hydrolysis and alcoholysis of palladium acetate. Angew Chem Int
Ed 54:6591–6594
5. Bizouard P, Testa C, Zinovyeva VA, Roger J, Hierso J-C (2016) Palladium–Polypyrrole
nanocomposites Pd@PPy for direct C–H functionalization of pyrroles and imidazoles with
bromoarenes. Synlett 27:1227–1231
6. Bray JTW, Ford MJ, Karadakov PB, Whitwood AC, Fairlamb IJS (2019) The critical role
played by water in controlling Pd catalyst speciation in arylcyanation reactions. React Chem
Eng 4:122–130
7. Brazier JB, Nguyen BN, Adrio LA, Barreiro EM, Leong WP, Newton MA, Figueroa SJA,
Hellgardt K, Hii KKM (2014) Catalysis in flow: operando study of Pd catalyst speciation and
leaching. Catal Today 229:95–103
8. Campeau L-C, Rousseaux S, Fagnou K (2005) A solution to the 2-Pyridyl organometallic crosscoupling problem: regioselective catalytic direct arylation of pyridine N-oxides. J Am Chem
Soc 127:18020–18021
9. Carole WA, Colacot TJ (2016) Understanding palladium acetate from a user perspective. Chem
Rev 22:7686–7695
10. Cassol CC, Umpierre AP, Machado G, Wolke SI, Dupont J (2005) The role of Pd nanoparticles
in ionic liquid in the Heck reaction. J Am Chem Soc 127:3298–3299
200
I. J. S. Fairlamb and N. W. J. Scott
the field ought to be fully examining homogeneous, heterogeneous and quasiheterogeneous–homogeneous behaviour. Having more developed and definite tests
will aid the catalysis and synthetic chemistry community at large in this respect.
At the time of writing, it is clear that the future is a very bright one for catalytic
cross-coupling chemistry, and there are many benefits and opportunities for the
employment of heterogeneous catalyst-type species. It remains to be seen whether
such catalysts will be more broadly applied in target-orientated synthesis, such as in
complex natural product synthesis. Hydrogenation on Pd/C is a mainstream reaction
in chemical synthesis, and it is the opinion of the authors that a step-change would be
seen in the broader adoption of similar catalysts in tricky synthetic transformations
(i.e. substrates containing a plethora of functionality and stereochemical information). Of particular note is that Pd/C is a preferred catalyst used in process chemistry.
The pioneering work by Glorius et al. has highlighted that conditions can be tuned to
grant Pd/C the ability to mediate complex C–H bond functionalisations. Thus, there
are many opportunities for this fascinating field going forwards, which can additionally be exploited in the synthesis of agrochemicals, pharmaceuticals and
advanced materials.
References
1. Adrio LA, Nguyen BN, Guilera G, Livingston AG, Hii KK (2012) Speciation of Pd(OAc)2 in
ligandless Suzuki–Miyaura reactions. Cat Sci Technol 2:316–323
2. Bao Y-S, Zhang D, Jia M, Zhaorigetu B (2016) Replacing Pd(OAc)2 with supported palladium
nanoparticles in ortho-directed CDC reactions of alkylbenzenes. Green Chem 18:2072–2077
3. Bao Y-S, Wang L, Jia M, Xu A, Agula B, Baiyin M, Zhaorigetu B (2016) Heterogeneous
recyclable nano-palladium catalyzed amidation of esters using formamides as amine sources.
Green Chem 18:3808–3814
4. Bedford RB, Bowen JG, Davidson RB, Haddow MF, Seymour-Julen AE, Sparkes HA,
Webster RL (2015) Facile hydrolysis and alcoholysis of palladium acetate. Angew Chem Int
Ed 54:6591–6594
5. Bizouard P, Testa C, Zinovyeva VA, Roger J, Hierso J-C (2016) Palladium–Polypyrrole
nanocomposites Pd@PPy for direct C–H functionalization of pyrroles and imidazoles with
bromoarenes. Synlett 27:1227–1231
6. Bray JTW, Ford MJ, Karadakov PB, Whitwood AC, Fairlamb IJS (2019) The critical role
played by water in controlling Pd catalyst speciation in arylcyanation reactions. React Chem
Eng 4:122–130
7. Brazier JB, Nguyen BN, Adrio LA, Barreiro EM, Leong WP, Newton MA, Figueroa SJA,
Hellgardt K, Hii KKM (2014) Catalysis in flow: operando study of Pd catalyst speciation and
leaching. Catal Today 229:95–103
8. Campeau L-C, Rousseaux S, Fagnou K (2005) A solution to the 2-Pyridyl organometallic crosscoupling problem: regioselective catalytic direct arylation of pyridine N-oxides. J Am Chem
Soc 127:18020–18021
9. Carole WA, Colacot TJ (2016) Understanding palladium acetate from a user perspective. Chem
Rev 22:7686–7695
10. Cassol CC, Umpierre AP, Machado G, Wolke SI, Dupont J (2005) The role of Pd nanoparticles
in ionic liquid in the Heck reaction. J Am Chem Soc 127:3298–3299
200
I. J. S. Fairlamb and N. W. J. Scott