Dear Colleagues,

Organic Synthesis is the science of making new, unexplored molecules. From simple building blocks to complex products. This is exactly what is at the heart of this Special Issue of “Molecules”.

Currently, Synthetic Organic chemists are able to design a multistep synthesis for almost any conceivable chemical structure by a rational approach based on the large toolbox of synthetic methods available and a retrosynthetic analysis. Traditionally, the reagents and conditions for each of the reaction steps need to be optimized to give a good yield and a pure product, with as little work as possible. To be useful in organic synthesis, methods must be reliable for a broad range of substrates. For complex organic molecules, however, executing such a “total” synthesis is still far from trivial, and is often neither simple nor elegant. The routes are often lengthy, with many reaction steps, employing a multitude of different, sometimes highly creative, protective group strategies, and/or using “metal-based”-catalysis. Truly sustainable production of complex, highly functionalized molecules for advanced application as (fine) chemicals and pharmaceuticals or in food, in materials, or in catalysis is still beyond any state of maturity. Thus, there is a clear need for the discovery and development of clean, atom- and step-efficient one-pot syntheses for the sustainable production of molecularly diverse and structurally complex organic molecules with high-added-values.

Mulicomponent reactions (MCRs) are increasingly appreciated as efficient synthesis tools to rapidly access complex products. With MCRs, molecules can be assembled from three or more starting materials in a one-pot process. MCRs involve the inherent formation of several bonds in a single operation, without isolating the intermediates, changing the reaction conditions, and often without adding further reagents. Therefore, MCRs address sustainability by atom-, step-, and, thus, eco-efficiency, reducing the number of intermediate steps and functional group manipulations and avoiding protective group strategies. Syntheses involving MCRs save time and energy (step efficiency) and proceed with high convergency (process efficiency). In addition, MCRs are ideally suited for combinatorial chemistry and library design, and are of great utility in medicinal chemistry, material science, recognition (host-guest) chemistry, and catalyst design. Notably, MCRs are believed to be crucial in exploiting the full potential of “diversity-oriented synthesis” (DOS) and “biology-oriented synthesis” (BIOS) design strategies for effective and functional library synthesis uncovering virgin areas of biologically relevant chemical space.

In this Special Issue of Molecules, research articles covering all areas of MCR-chemistry and related one-pot syntheses are welcomed to provide an interesting “snap-shot” of the current state-of-the-art in this exciting organic chemistry research field.

Prof. Romano V. A. Orru
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• organic synthesis
• multicomponent reaction
• diversity oriented synthesis
• atom- and step efficiency
• one-pot reactions
• cascade reactions