Total synthesis is the complete chemical synthesis of a complex molecule, often a natural product, from simple, commercially-available precursors. It usually refers to a process not involving the aid of biological processes, which distinguishes it from semisynthesis. Syntheses may sometimes conclude at a precursor with further known synthetic pathways to a target molecule, in which case it is known as a formal synthesis. Total synthesis target molecules can be natural products, medicinally-important active ingredients, known intermediates, or molecules of theoretical interest. Total synthesis targets can also be organometallic or inorganic, though these are rarely encountered. Total synthesis projects often require a wide diversity of reactions and reagents, and subsequently requires broad chemical knowledge and training to be successful.
The Suzuki reaction is an organic reaction, classified as a cross-coupling reaction, where the coupling partners are a boronic acid and an organohalide and the catalyst is a palladium(0) complex. It was first published in 1979 by Akira Suzuki, and he shared the 2010 Nobel Prize in Chemistry with Richard F. Heck and Ei-ichi Negishi for their contribution to the discovery and development of palladium-catalyzed cross-couplings in organic synthesis. This reaction is also known as the Suzuki–Miyaura reaction or simply as the Suzuki coupling. It is widely used to synthesize polyolefins, styrenes, and substituted biphenyls. Several reviews have been published describing advancements and the development of the Suzuki reaction. The general scheme for the Suzuki reaction is shown below, where a carbon-carbon single bond is formed by coupling an organoboron species (R1-BY2) with a halide (R2-X) using a palladium catalyst and a base.
Nanomaterial-based catalysts are usually heterogeneous catalysts broken up into metal nanoparticles in order to enhance the catalytic process. Metal nanoparticles have high surface area, which can increase catalytic activity. Nanoparticle catalysts can be easily separated and recycled. They are typically used under mild conditions to prevent decomposition of the nanoparticles.
The Negishi coupling is a widely employed transition metal catalyzed cross-coupling reaction. The reaction couples organic halides or triflates with organozinc compounds, forming carbon-carbon bonds (C-C) in the process. A palladium (0) species is generally utilized as the metal catalyst, though nickel is sometimes used. A variety of nickel catalysts in either Ni0 or NiII oxidation state can be employed in Negishi cross couplings such as Ni(PPh3)4, Ni(acac)2, Ni(COD)2 etc.
Platinum nanoparticles are usually in the form of a suspension or colloid of nanoparticles of platinum in a fluid, usually water. A colloid is technically defined as a stable dispersion of particles in a fluid medium.
Asymmetric hydrogenation is a chemical reaction that adds two atoms of hydrogen to a target (substrate) molecule with three-dimensional spatial selectivity. Critically, this selectivity does not come from the target molecule itself, but from other reagents or catalysts present in the reaction. This allows spatial information to transfer from one molecule to the target, forming the product as a single enantiomer. The chiral information is most commonly contained in a catalyst and, in this case, the information in a single molecule of catalyst may be transferred to many substrate molecules, amplifying the amount of chiral information present. Similar processes occur in nature, where a chiral molecule like an enzyme can catalyse the introduction of a chiral centre to give a product as a single enantiomer, such as amino acids, that a cell needs to function. By imitating this process, chemists can generate many novel synthetic molecules that interact with biological systems in specific ways, leading to new pharmaceutical agents and agrochemicals. The importance of asymmetric hydrogenation in both academia and industry contributed to two of its pioneers — William Standish Knowles and Ryōji Noyori — being awarded one half of the 2001 Nobel Prize in Chemistry.
An electrocatalyst is a catalyst that participates in electrochemical reactions. Electrocatalysts are a specific form of catalysts that function at electrode surfaces or, most commonly, may be the electrode surface itself. An electrocatalyst can be heterogeneous such as a platinized electrode. Homogeneous electrocatalysts, which are soluble, assist in transferring electrons between the electrode and reactants, and/or facilitate an intermediate chemical transformation described by an overall half reaction. Major challenges in electrocatalysts focus on fuel cells.
Hydrogen auto-transfer, also known as borrowing hydrogen, is the activation of a chemical reaction by temporary transfer of two hydrogen atoms from the reactant to a catalyst and return of those hydrogen atoms back to a reaction intermediate to form the final product. Two major classes of borrowing hydrogen reactions exist: (a) those that result in hydroxyl substitution, and (b) those that result in carbonyl addition. In the former case, alcohol dehydrogenation generates a transient carbonyl compound that is subject to condensation followed by the return of hydrogen. In the latter case, alcohol dehydrogenation is followed by reductive generation of a nucleophile, which triggers carbonyl addition. As borrowing hydrogen processes avoid manipulations otherwise required for discrete alcohol oxidation and the use of stoichiometric organometallic reagents, they typically display high levels of atom-economy and, hence, are viewed as examples of Green chemistry.
Carbon nanotube supported catalyst is a novel supported catalyst, using carbon nanotubes as the support instead of the conventional alumina or silicon support. The exceptional physical properties of carbon nanotubes (CNTs) such as large specific surface areas, excellent electron conductivity incorporated with the good chemical inertness, and relatively high oxidation stability makes it a promising support material for heterogeneous catalysis.
Nickel boride is the common name of materials composed chiefly of the elements nickel and boron that are widely used as catalysts in organic chemistry. Their approximate chemical composition is Ni2.5B, and they are often incorrectly denoted "Ni
2B" in organic chemistry publications.
In materials and electric battery research, cobalt oxide nanoparticles usually refers to particles of cobalt(II,III) oxide Co
3O
4 of nanometer size, with various shapes and crystal structures.
Iron–platinum nanoparticles are 3D superlattices composed of an approximately equal atomic ratio of Fe and Pt. Under standard conditions, FePt NPs exist in the face-centered cubic phase but can change to a chemically ordered face-centered tetragonal phase as a result of thermal annealing. Currently there are many synthetic methods such as water-in-oil microemulsion, one-step thermal synthesis with metal precursors, and exchanged-coupled assembly for making FePt NPs. An important property of FePt NPs is their superparamagnetic character below 10 nanometers. The superparamagnetism of FePt NPs has made them attractive candidates to be used as MRI/CT scanning agents and a high-density recording material.
Xie Yi FRSC is a Chinese chemist. She is a member of the Chinese Academy of Sciences and a fellow of the Royal Society of Chemistry. She is a professor and doctoral supervisor at University of Science and Technology of China.
Irshad Hussain is a Pakistani Scientist in the field of chemistry and among the few pioneers to initiate nanomaterials research in Pakistan.
Brandi Michelle Cossairt is an American chemist specializing in synthetic inorganic and materials chemistry. She is an Associate Professor of Chemistry at University of Washington.
David Zitoun is an Israeli chemist and materials scientist.
Sophie Carenco is a researcher at the French National Center for Scientific Research, working on nanochemistry at the Laboratory of Condensed Matter Chemistry of Paris. Her research focuses on novel synthetic routes of exotic nanomaterials for energy application such as CO2 capture.
Daniel Kwabena Dakwa Bediako is a Ghanaian-British chemist. He is currently Assistant Professor at the University of California, Berkeley, and is the Cupola Era Professor in the College of Chemistry. His research considers charge transport and interfacial charge transfer in two-dimensional materials and heterostructures. He is also a member of the Editorial Advisory Board of the Journal of the American Chemical Society (JACS).
Xile Hu is a Swiss chemist specialized in catalysis. He is a professor in chemistry at EPFL and leads the Laboratory of Inorganic Synthesis and Catalysis at the School of Basic Sciences.
Mita Dasog is an assistant professor at Dalhousie University in Nova Scotia, Canada. She has received the Emerging Professional Award, the Canadian Council of University Chemistry Chairs Doctoral Award, is a “Top 25” Global Young Scientist in Sustainable Research, and is one of the top 150 women in STEM for her outreach efforts with youth and young women.
