Editorial [Hot Topic: Recent Progress in the Synthesis and Applications of Cyclic Compounds (Guest Editor: Ruimao Hua)]

When my proposal of a special issue entitled “Recent Progress in the Synthesis and Applications of Cyclic Compounds” for Current Organic Chemistry was approved by the Editor-in-Chief of the journal in February 2009, I was very happy to start the edition of this special issue that I immediately released a call for manuscripts on my laboratory's website (http://chem.tsinghua.edu.cn/huarm/) and sent about 30 invitation letters to potential authors. A month later, nearly 15 authors agreed to make a contribution for this special issue. Finally, 10 papers from different universities and institutes with authors hailing from 10 countries were selected for publication with respect to different themes in the synthesis and applications of cyclic compounds. This special issue involves topics concerning the synthesis and applications of bismuth-containing heterocyclic compounds contributed by Dr. S. Shimada (National Institute of Advanced Industrial Science and Technology (AIST), Japan), applications of carbon dioxide in the synthesis of heterocyclic compounds summarized by Dr. L. He and coworkers (Nankai University, China), recent developments in the synthesis and application of three- and four-membered heterocycles written by Dr. B. Myrboh and co-workers (North Eastern Hill University, India), recent advances in the regioselective synthesis of pyrazoles reviewed by Dr. H. Shin and co-workers (LG Life Sciences, Ltd./R & D, Korea), synthesis of five-membered sulfur-heterocycles via 1,5- dipolar electrocyclization of thiocarbonyl ylides and related processes reviewed by Drs. G. Mloston and H. Heimgartner (University of Lodz, Poland and University of Zurich, Switzerland), recent advances in the synthesis of five-membered heterocycles contributed by Dr. S. Hameed and T. Akhtar (Quaid-I-Azam University, Pakistan), recent achievements in the chemistry of 1,2-diazines written by Dr. I. I. Mangalagiu (“Al. I. Cuza” University of Iasi, Romania), recent progress in the synthesis and applications of heterocycles derived from enaminonitrile revieweded by Dr. S. Bondock and co-workers (Mansoura University, Egypt), isocoumarin and its derivatives: an overview on their synthesis and application, contributed by Dr. S. Pal and co-workers (MNR Degree and PG College, India), and cycloaddition of alkynes: atom-economic protocols for constructing six-membered cycles, submitted by myself, with co-authors Miss Maria Victoria A. Abrenica (Wellesley College, USA) and Ping Wang (Tsinghua University, China). Although only 10 review papers are included in this special issue, more than 500 reactions are described and over 1100 literature references are cited. I believe this issue has a comprehensive coverage of important and up-to-date reactions for the synthesis of cyclic compounds and their applications in organic synthesis. As guest editor, I would first like to acknowledge all the authors who have made contributions to this special issue. I deeply thank all the referees for their exceedingly helpful comments on improving the quality of the manuscripts. I wish to express a special thanks to Miss Maria Victoria A. Abrenica, one of the authors in this special issue, for her help in proofreading all the manuscripts. Finally, a huge thanks to Dr. Atta-ur-Rahman, Editor-in-Chief of Current Organic Chemistry for his kind invitation to me to edit this special issue as guest editor, and to Dr. D. Akhter, assistant manager of the publication department at Bentham Science Publishers, for her kind communications throughout the whole process of editing. I look forward to a fruitful cooperation with you all again in the near future! This special issue is dedicated to the occasion of the 100th anniversary of Tsinghua University in 2011.