Reactions carried out with substoichiometric quantities of organic molecules as catalysts have received much attention over the past decade. This review highlights progress in 2011 towards highly enantioselective organocatalytic systems and the natural product/biologically active compounds that can be prepared using these types of processes.
This report highlights mechanistic work pertaining to polar reactions published in 2011. A range of topics is covered, spanning many different fields in chemistry, and as is often the case with much mechanistic work, the specific details of the work may span a number of the headings used to divide up this review. As such these headings should be used as guidelines. Areas such as supramolecular chemistry, biological systems and model systems, and solvent interactions are all featured.
Visible light photoredox catalysis is gradually replacing traditional radical reagents for the initiation and propagation of radical reactions in organic synthesis. This year has seen this methodology employed to generate high-energy aryl radicals and N-centred radicals. Photoredox catalysis played a pivotal role in the synthesis of (-)- aplyviolene, demonstrating the potential of this methodology. Another of this year's highlights was the remarkably simple asymmetric synthesis of pyrrolidines developed by MacMillan.
This review covers the literature on marine natural products published in 2002. As in previous years there has been enormous interest in the structure elucidation, synthesis, activity and ecology of marine natural products. Marine sources produce compounds of new structural types with an intriguing array of biological activities. Sponges are the commonest organisms to be studied, however, algae, bacteria and fungi have been far from neglected. The bioactivity-guided extraction and purification of crude extracts has produced highly potent compounds. Marine species have been interacting chemically for billions of years and it is no wonder that there have evolved natural products with such high activity. Some are highly toxic whereas others have very selective activities and have the potential to be used therapeutically.
This report is a personal selection of synthesis methods involving organoheteroatom chemistry from the primary chemical literature of 2012.
This review showcases some exemplary total syntheses of natural products reported in the scientific literature in 2010.
This report highlights selected advances in some of the most commonly used oxidation and reduction reactions, focusing on the literature from 2012. The structure of this review follows that of the previous years report (J. K. Howard and C. J. T. Hyland, Annu. Rep. Prog. Chem., Sect. B: Org. Chem., 2012, 108, 29-52 (ref. 1)). In the field of oxidation a number of important advances have been made. Notably, the group of Miller has reported a peptide-based catalyst that allows the selective epoxidation of polyenes (P. A. Lichtor and S. J. Miller, Nat. Chem., 2012, 4, 990). Meanwhile, the Tomkinson group has reported osmium-free alkene dihydroxylation reactions with cyclopropyl-derived malonoyl peroxides (S. Picon, M. Rawling, M. Campbell and N. C. O. Tomkinson, Org. Lett., 2012, 14, 6250-6253). In the area of reduction methods the Chirik group has made an exciting breakthrough in the use of non-precious metal enantiopure C-1-symmetric bis(imino) pyridine cobalt complexes for asymmetric hydrogenation of a range of styrene derivatives in up to 96% ee (S. Monfette, Z. R. Turner, S. P. Semproni and P. J. Chirik, J. Am. Chem. Soc., 2012, 134, 4561-4564). Meanwhile Kuwano et al. have reported the first PhTrap-ruthenium catalysed asymmetric hydrogenation of naphthalenes (R. Kuwano, R. Morioka, M. Kashiwabara and N. Kameyama, Angew. Chem., Int. Ed., 2012, 51, 4136-4139).
This review highlights some of the advances that have been made in the study of donor-acceptor interactions and their applications in the construction of functional supra-molecular architectures in 2012. The review is organised into three broad sections encompassing light-harvesting photovoltaics, donor-acceptor co-polymers and mechanically interlocked molecules.
This review summarizes advances made in the field of computational organic chemistry in 2012, focussing on the following topics: (1) organic structure and bonding, (2) organocatalytic mechanisms, (3) computational structural elucidation, (4) dynamic effects, (5) methodological advances and (6) computational organic chemistry on the web.
Radical reactions endear themselves to organic chemists due to their ability to mediate otherwise difficult transformations (e.g. functionalization of unactivated hydrocarbons), and the associated challenges with predicting and/or controlling their reactivity. This manuscript provides an overview of the most significant developments in organic radical chemistry in 2012, with particular attention paid to the mechanistic attributes identified in these contributions. It is loosely structured to provide the broadest possible coverage, and is organized in sections highlighting (1) radical reactions that are either initiated or mediated by transition metals, (2) reactions not involving any transition metals, and (3) reactions of biological molecules or models thereof that provide insight on the roles of organic radicals in biological processes.
This review summarizes a number of articles published in 2011 describing mechanisms of pericyclic reactions. The types of reactions studied were of the cycloaddition sort (e. g., [2+1], [2+2], [3+2], [4+2], etc.), as well as sigmatropic (e.g., [1,2], [1,3], [3,3] shifts, etc.), group transfer (e.g., ene), and electrocyclic types. Interestingly, the literature on pericyclic cascade reactions was quite rich in 2011.
NMR spectroscopy continues to evolve, with publications in 2011 providing an eclectic collection of applications, advances and incremental improvements. Publications highlights include: DNP in liquids and solids, decoupling effects at high spinning speed in solid-state, results from the 80 kHz spinning-speed 1 mm MAS rotor, enhanced diffusion methods, results from the new 1.0 GHz magnet, an intent to create a 1.3 GHz magnet, results from the 2.6 GHz pulsed-magnet, a cryogen-free MRI, and the use of multiple receivers to acquire multiple experiments within the same pulse sequence. I am indebted to the great and the good whose work has been reported here, all credit is theirs; errors, omissions and blame are all mine.
This report reviews significant developments in applications of biological catalysis in synthetic organic chemistry for the year 2011. In the area of hydrolase-catalysed biotransformations, lipases have been used in dynamic kinetic resolutions of amines at low-temperature using radical-based racemisation methods. A system has also been developed for the lipase catalysed desymmetrisation of allenic diols. An unusual promiscuous activity of formate dehydrogenase has been described in which the enzyme catalysed a hydrolytic reaction. In reductase biotransformations, ene reductases of the Old Yellow Enzyme family have been applied to the asymmetric reduction of Baylis-Hillman adducts and also shown, in some cases, to catalyse oxazete formation in the transformation of nitro-alkenes. The carbon-carbon bond forming enzyme benzaldehyde lyase was reported to catalyse N-hydroxamic acid formation from benzaldehydes and nitrosobenzenes. An (R)-selective arylmalonate decarboxylase has been engineered either to act as a racemase or to catalyse decarooxylation with inverted enantioselectivity. New developments in oxidase biocatalysis include the application of flavin-dependent Bereberine Bridge Enzyme to the resolution of reticuline-like substrates through carbon-carbon bond formation. A Baeyer-Villiger monooxygenase catalysed a dynamic kinetic resolution using racemic substrates susceptible to racemisation at alkaline pH. Cytochromes P450 have been applied to the oxidation of gaseous alkanes including methane, in the presence of perfluoro alkanoic acids. The peroxygenase AaeAPO has been used to catalyse hydroxylation and epoxidation reactions in photobiocatalytic systems. Finally, artificial metalloenzymes based on the streptavidin-biotin system have now been applied to asymmetric imine reduction, dihydroxylation and alkene metathesis.
This report reviews the 2011 literature on reactivity in organised assemblies in aqueous systems. The basic scope of the report is broadly as before, and this year's themes are as follows: (1) reactivity in micelles, including medium effects and compartmentalisation, micelle-assisted catalysis and functionalised amphiphiles, (2) DNA-based approaches to influencing reactivity, including DNA-templated reactions and DNA-based catalysis, and (3) nanoparticle-based assemblies for use in catalysis, including modulation of nanoparticle catalysis through thermoresponsive polymer shells and nanoparticle-supported catalysts.
