http://www.mdpi.com/journal/molecules/special_issues/cross-coupling/ Dear Colleagues Cross-coupling reactions are key steps in the synthesis of a number of bioactive molecules of interest in pharmaceuticals, agrochemicals, cosmetics and more generally in fine chemicals. These reactions, including substitution of an aryl, vinyl or aklyl halide by nucleophile under transition metal catalysed procedures, have been the focus of many academic and industrial research groups leading to significant improvements during the last two decades. This special issue of Molecules dedicated to Cross-coupling Reactions calls for both fundamental and applied contributions in this field that remain a hot topic for both academics and industrials. Special attention will be paid to original contributions and feature articles reporting new or improved cross-coupling methodologies. Review papers are strongly encouraged, with special interests to those focusing on mechanistic aspects. Dr. Laurent Djakovitch Guest Editor {snippet name="submission_info"} http://www.mdpi.com/1420-3049/16/6/5241/ N-containing heteroaromatics are important substructures found in numerous natural or synthetic alkaloids. The diversity of the structures encountered, as well as their biological and pharmaceutical relevance, have motivated research aimed at the development of new economical, efficient and selective synthetic strategies to access these compounds. Over more than 100 years of research, this hot topic has resulted in numerous so-called “classical synthetic methods” that have really contributed to this important area. However, when the selective synthesis of highly functional heteroaromatics like indoles, quinolones, indoxyls, etc. is considered these methods remain limited. Recently transition metal-catalysed (TM-catalysed) procedures for the synthesis of such compounds and further transformations, have been developed providing increased tolerance toward functional groups and leading generally to higher reaction yields. Many of these methods have proven to be the most powerful and are currently applied in target- or diversity-oriented syntheses. This review article aims at reporting the recent developments devoted to this important area, focusing on the use of heterogeneous catalysed procedures that include either the formation of the heterocyclic ring towards the nuclei or their transformations to highly substituted compounds. http://www.mdpi.com/1420-3049/16/6/5241/ Thu, 23 Jun 2011 00:00:00 CEST Molecules 2011-06-23 16 6 Review 5241 5267 1420-3049 Recent Advances in the Synthesis of N-Containing Heteroaromatics via Heterogeneously Transition Metal Catalysed Cross-Coupling Reactions 2011-06-23 doi: 10.3390/molecules16065241 Laurent Djakovitch Nelly Batail Marie Genelot http://www.mdpi.com/1420-3049/16/2/1129/ The increasing application of positron emission tomography (PET) in nuclear medicine has stimulated the extensive development of a multitude of new radiotracers and novel radiolabeling procedures with the most prominent short-lived positron emitters carbon-11 and fluorine-18. Radiolabeling with these radionuclides represents a remarkable challenge. Special attention has to be paid to synthesis time and specific labeling techniques due to the short physical half life of the respective radionuclides 11C (t1/2 = 20.4 min) and 18F (t1/2 = 109.8 min). In the past, numerous transition metal-catalyzed reactions were employed in organic chemistry, even though only a handful of these coupling reactions were adopted in radiochemical practice. Thus, the implementation of modern synthesis methods like cross-coupling reactions offers the possibility to develop a wide variety of novel radiotracers. The introduction of catalysts based on transition metal complexes bears a high potential for rapid, efficient, highly selective and functional group-tolerating incorporation of carbon-11 and fluorine-18 into target molecules. This review deals with design, application and improvement of transition metal-mediated carbon-carbon as well as carbon-heteroatom cross-coupling reactions as a labeling feature with the focus on the preparation of radiolabeled compounds for molecular imaging. http://www.mdpi.com/1420-3049/16/2/1129/ Wed, 26 Jan 2011 00:00:00 CET Molecules 2011-01-26 16 2 Review 1129 1165 1420-3049 Cross-Coupling Reactions as Valuable Tool for the Preparation of PET Radiotracers 2011-01-26 doi: 10.3390/molecules16021129 Marc Pretze Philipp Große-Gehling Constantin Mamat http://www.mdpi.com/1420-3049/16/1/38/ Pd was loaded on ultra stable Y (USY) zeolites prepared by steaming NH4-Y zeolite under different conditions. Heck reactions were carried out over the prepared Pd/USY. We found that H2 bubbling was effective in improving not only the catalytic activity of Pd/USY, but also that of other supported Pd catalysts and Pd(OAc)2. Moreover, the catalytic activity of Pd/USY could be optimized by choosing appropriate steaming conditions for the preparation of the USY zeolites; Pd loaded on USY prepared at 873 K with 100% H2O gave the highest activity (TOF = 61,000 h−1), which was higher than that of Pd loaded on other kinds of supports. The prepared Pd/USY catalysts were applicable to the Heck reactions using various kinds of substrates including bromo- and chloro-substituted aromatic and heteroaromatic compounds. Characterization of the acid properties of the USY zeolites revealed that the strong acid site (OHstrong) generated as a result of steaming had a profound effect on the catalytic activity of Pd. http://www.mdpi.com/1420-3049/16/1/38/ Fri, 24 Dec 2010 00:00:00 CET Molecules 2010-12-24 16 1 Article 38 51 1420-3049 Enhancement in the Catalytic Activity of Pd/USY in the Heck Reaction Induced by H2 Bubbling 2010-12-24 doi: 10.3390/molecules16010038 Kazu Okumura Takuya Tomiyama Sayaka Moriyama Ayaka Nakamichi Miki Niwa http://www.mdpi.com/1420-3049/15/12/9157/ A heterogeneous catalyst, nanosized MCM-41-Pd, was used to catalyze the Sonogashira coupling of aryl and heteroaryl halides with terminal alkynes in the presence of CuI and triphenylphosphine. The coupling products were obtained in high yields using low Pd loadings to 0.01 mol%, and the nanosized MCM-41-Pd catalyst was recovered by centrifugation of the reaction solution and re-used in further runs without significant loss of reactivity. http://www.mdpi.com/1420-3049/15/12/9157/ Fri, 10 Dec 2010 00:00:00 CET Molecules 2010-12-10 15 12 Article 9157 9173 1420-3049 Sonogashira Reaction of Aryl and Heteroaryl Halides with Terminal Alkynes Catalyzed by a Highly Efficient and Recyclable Nanosized MCM-41 Anchored Palladium Bipyridyl Complex 2010-12-10 doi: 10.3390/molecules15129157 Bo-Nan Lin Shao-Hsien Huang Wei-Yi Wu Chung-Yuan Mou Fu-Yu Tsai