Flow chemistry involves the use of channels or tubing to conduct a reaction in a continuous stream rather than in a flask Flow equipment provides chemists with unique control over reaction parameters enhancing reactivity or in some cases enabling new reactions This relatively young technology has received a remarkable amount of attention in the past decade with many reports on what can be done in flow Until recently, however, the question, “Should we do this in flow?” has merely been an afterthought This review introduces readers to the basic principles and fundamentals of flow chemistry and critically discusses recent flow chemistry accounts

The Hitchhiker's Guide to Flow Chemistry

Multicomponent reactions: advanced tools for sustainable organic synthesis

It was in 1963 that Huisgen laid out the classification of 1,3-dipoles and the concepts for 1,3-dipolar cycloaddition reactions, although it was not until 1976 that the first intramolecular 1,3-dipolar cycloaddition reaction of an azomethine ylide was reported. Since then, impressive developments have been described in this area, with the establishment of various useful methods for the formation of azomethine ylides and the determination of the requirements for a successful intramolecular cycloaddition reaction. Use of this methodology for the synthesis of pyrrolidineand pyrrole-containing natural products has been expanding rapidly. This review aims to describe the background and mechanisms of azomethine ylide formation and intramolecular cycloaddition, giving a critical account including the very first example and covering to early 2005. It is hoped that this review will be a useful resource for chemists interested in cycloaddition reactions and will inspire further exciting developments in this area. Cycloaddition reactions are one of the most important class of reactions in synthetic chemistry. Within * Corresponding author. Tel: +44 (0)114 222 9428. Fax: +44 (0)114 222 9346. E-mail: i.coldham@sheffield.ac.uk. † University of Sheffield. ‡ Tripos Discovery Research Ltd. Iain Coldham (b. 1965) is a Reader in Organic Chemistry at the University of Sheffield. He obtained his undergraduate degree and Ph.D. from the University of Cambridge, completing his Ph.D. in 1989 under the supervision of Stuart Warren. After postdoctoral studies at the University of Texas with Philip Magnus, he joined the staff in 1991 at the University of Exeter, U.K. In 2003, he moved to the University of Sheffield where he is involved in research on chiral organolithium compounds and on dipolar cycloaddition reactions in synthetic organic chemistry.

Intramolecular dipolar cycloaddition reactions of azomethine ylides.

The use of N-heterocyclic carbenes (NHCs) in chemistry has developed rapidly over the past twenty years. These interesting compounds are predominantly employed in organometallic chemistry as ligands for various metal centres, and as organocatalysts able to mediate an exciting range of reactions. However, the sheer number of NHCs known in the literature can make the appropriate choice of NHC for a given application difficult. A number of metrics have been explored that allow the electronic properties of NHCs to be quantified and compared. In this review, we discuss these various metrics and what they can teach about the electronic properties of NHCs. Data for approximately three hundred NHCs are presented, obtained from a detailed survey of the literature.

Quantifying and understanding the electronic properties of N-heterocyclic carbenes

Colloidal inorganic nanocrystals stand out as an important class of advanced nanomaterials owing to the flexibility with which their physical-chemical properties can be controlled through size, shape, and compositional engineering in the synthesis stage and the versatility with which they can be implemented into technological applications in fields as diverse as optoelectronics, energy conversion/production, catalysis, and biomedicine. The use of microwave irradiation as a non-classical energy source has become increasingly popular in the preparation of nanocrystals (which generally involves complex and time-consuming processing of molecular precursors in the presence of solvents, ligands and/or surfactants at elevated temperatures). Similar to its now widespread use in organic chemistry, the efficiency of "microwave flash heating" in dramatically reducing overall processing times is one of the main advantages associated with this technique. This Review illustrates microwave-assisted methods that have been developed to synthesize colloidal inorganic nanocrystals and critically evaluates the specific roles that microwave irradiation may play in the formation of these nanomaterials.

Jonathan D. Moseley

Papers

A critical assessment of the greenness and energy efficiency of microwave-assisted organic synthesis

A Comparison of Commercial Microwave Reactors for Scale-Up within Process Chemistry

A Commercial Continuous Flow Microwave Reactor Evaluated for Scale-Up

Scaling-Out Pharmaceutical Reactions in an Automated Stop-Flow Microwave Reactor

Beyond the Numbers: Charting Chemical Reaction Space