Description
ABSTRACT
Research on transition metal catalysis is advancing day by day. Unlike the conventional precious metal based catalysis, the researchers are now focusing on exploring the applicability of earth-abundant first row transition elements as catalysts for C-C coupling reactions. Among them, the Suzuki-Miyaura coupling reaction greatly impacts the industrial catalytic processes. Nickel catalyzed coupling is a great topic of interest for organic chemists over the last few decades. But, the mitigation of halogen waste is the major environmental concern associated with the traditional Suzuki coupling reaction. In this concern, various abundant and cheap electrophiles such as carboxylic acid derivatives, phenol derivatives, and amides have a remarkable priority in replacing the organic halides. In this strategy, the core C-O and C-N bonds were activated to form the C-C coupling products. Based on the advantages of Ni-catalysis, the research is directed towards exploring the various Ni-based catalytic systems for the successful Suzuki coupling reaction by activating C-O and C-N bonds. The recent reports are highly motivated toward green metrics. In the current review, we would like to summarize the recent advances in the Ni-catalyzed Suzuki coupling via C-O and C-N bond activation.
TABLE OF CONTENTS
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWLEDGEMENT
ABSTRACT
TABLE OF CONTENT
CHAPTER ONE
- INTRODUCTION
- Background Of The study
- Problem Statement
- Aim/Objective Of The study
- Scope of the study
- Significance of the study
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 Cross-coupling reactions
2.2 Overview of Nickel
2.2.1 Isotopes of nickel
2.2.2 Occurrence of Nickel
2.2.3 Nickel Compounds
2.3 Historical background of the Nickel
2.4 Nickel Catalysis
CHAPTER THREE
3.0 METHODOLOGY
3.1 Recent advances in the nickel catalysts
CHAPTER FOUR
Discussion
CHAPTER FIVE
5.0 Conclusion and Recommendation
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Cross coupling reactions via transition metal catalysis hold an important place in the field of organic synthesis (Jana et al., 2011; Beletskaya and Ananikov, 2011; Nicolaou et al., 2005), in which their importance has been recognized by the scientific community by being rewarded with the Nobel prize (Johansson Seechurn et al., 2012). Suzuki-Miyaura (Suzuki, 1985), Heck (2005), Negishi (Milstein and Stille, 1979), Kumada (Miyaura, 2004), Sonagashira (Sonogashira et al., 1991), and Hiyama (Nakao and Hiyama, 2011) are the various cross-coupling reactions for the C-C and C-Hetero atom bond formation technologies with a high impact from lab scale to the industrial levels. Among them, Suzuki-Miyaura coupling is a highly versatile reaction for the C-C bond formation in which the Noble prize in chemistry was grabbed to its credit along with Heck and Negishi coupling reactions in 2010 (Thomas and Denmark, 2016). Suzuki coupling reaction has proved its potential since its discovery in 1979 to date in synthesizing a wide variety of pharmaceuticals, intermediates, specialty chemicals, supramolecules, polymers, etc (Blakemore, 2016). Suzuki coupling is a palladium-catalyzed cross-electrophile coupling reaction between organoboronic compounds and organic halides or pseudo halides. The reaction conditions include mild temperatures employing base and phosphine based ligands. The versatility of the reaction lies in the facile coupling between the organoboronic compounds and the organic halides that are comparatively having electrophilicity difference via three important steps such as oxidative addition, transmetalation, and reductive elimination which were easily facilitated by palladium catalysis (Devendar et al., 2018). Moreover, organoboron reagents are less toxic and easily available compounds with good stability in ambient conditions (Miyaura and Suzuki, 1995).
Palladium based catalysis for the Suzuki-Miyaura (SM) coupling reaction is highly studied by various research groups within the 40 years of its research history. Even, the improvements in nanotechnology have also contributed to the developments in the reaction by employing various palladium nanoparticles, heterogeneous palladium on various supports, etc (Hong et al., 2020; Wolfson and Levy-Ontman, 2020; Kalidindi and Jagirdar, 2012). Apart from this, successful ppm level palladium based catalysis is also established (Handa et al., 2015, 2016; Roy and Uozumi, 2018). Even the Pd-catalyzed symmetric versions of the SM coupling reaction are also available (Johansson Seechurn et al., 2012; Zhang and Wang, 2015; Shen et al., 2019). The sustainable developments in the Pd-based SM reaction with a broad range of tolerable substrates have attracted organic chemists. Later on, realizing the hazardous impacts of halide wastes different coupling partners such as pseudo halides, carboxylic acid derivatives, and amides are also explored by various researchers to replace the organic halides (Wang et al., 2016; Liu and Szostak, 2018; Zhang et al., 2021). These developments have made the reaction more sustainable and have become the preferential choice in terms of industrial scale up reactions also.
Although, the developments in palladium catalysis are appreciable the cost of palladium is too high than the easily available first row transition metals (Peng et al., 2019). This made the researchers work on the best alternatives for palladium and the various reports have evaluated the efficiency of nickel on the SM coupling reaction successfully. Even though there are numerous developments in the SM coupling reaction, Nickel catalysis had a great impact in the last decade. After a decreased interest in conventional SM coupling reactions incorporation of Nickel as a catalyst has again demanded the chemists make advancements in this field. This growing factor is highly impactful in terms of industrial chemistry, which has grasped our attention. In fact, Ni is a highly earth abundant metal and is found to be much cheaper than that palladium (Du and Eisenberg, 2012), which has grasped the attention of organic chemists. Comparing the chemistry of Pd and Ni, palladium is commonly exhibited in Pd(0)/Pd(II) redox states (Johansson and Colacot, 2010; Hickman and Sanford, 2012) and the applicability of high valent palladium is currently under investigation. But, nickel is a first row transition metal with relatively less size than that of palladium, which makes it more nucleophilic and typically exhibits Ni(0)/Ni(II) as well as high valent states such as Ni(I)/Ni(III) (Rosen et al., 2011). These salient features of the nickel are more interesting in exploring its catalytic activity and the researchers have successfully established the Ni-catalyzed SM cross-coupling reaction with high yields compatible with the palladium (Ramgren et al., 2013). Apart from SM, the versatility of nickel based catalysts was successfully demonstrated by extensive studies on C-C and C-Hetero atom bond forming reactions employing various electrophiles that which were less reactive even in the presence of Pd (Diccianni and Diao, 2019), apart from the advantages in the case of the Ni as an alternative for the Pd, the discouraging factor is the loading of high amounts of Ni catalysts in all the earlier reports. Rather, the current status of research on Pd based catalysts has achieved the level of employing ppm levels of palladium for the SM coupling reaction. Although significant growth was observed in the case of Ni-catalysis, but the high catalyst loading is found to be the major concern to be focussed on. In fact, 5 mol% to 10 mol% levels of the catalyst loading was observed when Ni-catalyst was employed, wherein 0.1 mol% of catalyst loading instances were reported with the Pd (Akporji et al., 2020; Takale et al., 2019; Landstrom et al., 2018; Chatterjee and Ward, 2016). But as it is certain that the research progresses day by day and it is astonishing that the different versions of SM coupling reaction are now designed with the various Ni as a catalytic source. In the same way we may expect the ppm level Ni-catalyzed SM reaction from the dynamic research groups in the scientific community.
1.2 Problem statement
Nickel is an important catalyst that has attracted particular interest from organic chemists since the 1970s, both for cross-coupling and for a range of reactions of alkenes and alkynes. Tremendous advances have been made in nickel catalysis over the past decade. Several key properties of nickel, such as facile oxidative addition and ready access to multiple oxidation states, have allowed the development of a broad range of innovative reactions. In recent years, these properties have been increasingly understood and used to perform transformations long considered exceptionally challenging. Here we discuss some of the most recent and significant developments in homogeneous nickel catalysis, with an emphasis on both synthetic outcome and mechanism.
1.3 Aim and Objectives of the study
The main aim of this work is to carry out a research on the research progress of nickel catalysts in cross-coupling reactions.The objectives of the study are:
- To review different progress of nickel catalysts
- To carry out an overview of nickel catalysts
- To carry out a study of different types of cross-coupling reactions
1.4 Scope / Limitation of the study
The scope of this work covers on more recent advances in the use of homogeneous nickel catalysis in small-molecule synthesis, including nickel-mediated cross-coupling reactions. In this work different types of cross coupling reaction shall be discussed.
1.5 Significance of the study
This study will serve as a means of studying the importance of cross-coupling reactions stand among the most important reactions in chemistry. This study will also serve as a means of studying Advances in cross-coupling reactions that have been developed with the aim to expand the synthetic utility of the methodology, through the involvement of new components, reaction conditions, and therefore, novel synthetic applications.
CHAPTER FIVE
CONCLUSION AND RECOMMENDATION
Realizing the importance of Ni-catalysis, the present review summarizes the recent developments in the contribution of Ni-catalysis to the highly important SM coupling reaction. C-O and C-N bond activation for the C-C bond activation is an intellectual aspect that breaks the origins of traditional SM coupling. Although the developments in the Pd-catalysis concerning SM coupling of the same fashion are encouraging but suffers from the high cost of various commercially available Pd catalysts.
