Introduced to the Market in the Last Decade (2001−2011) Jiang Wang,† María Sańchez-Rosello,́‡,§ Jose ́ Luis Aceña, Carlos del Pozo,‡ Alexander E. Sorochinsky, Santos Fustero,*,‡,§ Vadim A. Soloshonok,* and Hong Liu*,† †Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China ‡Department of Organic Chemistry, Faculty of Pharmacy, University of Valencia, Av. Vicente Andreś Estelleś, 46100 Burjassot, Valencia, Spain Laboratorio de Molećulas Orgańicas, Centro de Investigacioń Príncipe Felipe, C/ Eduardo Primo Yuf́era 3, 46012 Valencia, Spain Department of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel Lardizab́al 3, 20018 San Sebastian, Spain IKERBASQUE, Basque Foundation for Science, Alameda Urquijo, 36-5 Plaza Bizkaia, 48011 Bilbao, Spain Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, Murmanska Street 1, 02660 Kyiv-94, Ukraine

Fluorine in pharmaceutical industry: fluorine-containing drugs introduced to the market in the last decade (2001-2011).

2.3. [4 + 4] Cycloadditions 1058 2.4. Photocycloadditions of Aromatic Compounds 1058 2.4.1. Benzene Derivatives 1058 2.4.2. Condensed Aromatic Compounds 1060 3. Photochemical Rearrangements 1061 4. Cyclizations 1064 4.1. Pericyclizations 1064 4.2. Norrish−Yang Reaction 1066 5. Photochemical Extrusion of Small Molecules 1067 6. Photochemical Electron Transfer 1068 6.1. Photochemical Electron-Transfer Reactions with a Catalytic Sensitizer 1068

Photochemical Reactions as Key Steps in Organic Synthesis

Helicenes: synthesis and applications.

Evolution in the field of the total synthesis of natural products has led to exciting developments over the last decade. Numerous chemoselective and enantioselective methodologies have emerged from total syntheses, resulting in efficient access to many important natural product targets. This Review highlights recent developments concerning dearomatization, a powerful strategy for the total synthesis of architecturally complex natural products wherein planar, aromatic scaffolds are converted to three-dimensional molecular architectures.

Dearomatization Strategies in the Synthesis of Complex Natural Products

Asymmetric Organocatalytic Cyclization and Cycloaddition Reactions

For many years [n]helicenes, nonplanar ortho-fused aromatic compounds that exhibit helical chirality, were regarded as little more than an academic curiosity. More recently, helicene chemistry has grown from the stage of a descriptive field of aesthetic and curious molecules to an important field of research owing to the extraordinary optical and electronic properties of these compounds, closely associated to their inherent chirality. Though useful, the classical synthesis of helicenes based on the oxidative photocyclization of stilbene-type precursors has been hampered by fundamental drawbacks from evolving into a really convenient method for preparing these molecules. This has led to the development of several new methodologies during the last decade which provide useful alternatives for the synthesis of this type of helical skeleton. Among them, the pioneering work of Katz and Liu led to the production of racemic helicene bisquinones through a Diels–Alder approach (Scheme 1), supplemented by an efficient procedure for effecting the required resolutions. Despite remarkable progress in helicene chemistry, the task of developing new, short, and efficient strategies to racemic and enantiopure helicenes which fulfill criteria of atom economy remains a challenge. For example, the first nonphotochemical preparation of [7]helicene, which was the first carbohelicene to be synthesized by dehydrophotocyclization, was not described until 1999 when Gingras and Dubois reported a five-step approach using a “carbenoid coupling” strategy (Scheme 2). Biphenanthrol 1, obtained by oxidative Cu-promoted coupling of 3-phenanthrol, was treated with triflic anhydride followed by addition of MeMgBr in the presence of a nickel catalyst to afford derivative 2 in 62% yield. After bromination of 2 and “carbenoid coupling” of dibromide 3 with excess LiHMDS, [7]helicene was obtained in 75% yield. A related strategy was presented in 2000 by Rajca and co-workers for the synthesis of a novel oligothiophene 4 (Scheme 3), in which the thiophene rings are cross-conjugated and annelated into a helix. The synthetic route consisted of two iterations using 3,4-dibromothiophene and compound 6 as the functionalized starting modules. In each iteration, Scheme 3. Iterative (“connection”–“annelation”) synthesis of racemic carbon–sulfur helicene 4. TMS= trimethylsilyl, LDA= lithium diisopropylamide. Scheme 2. First nonphotochemical synthesis of [7]helicene by a “carbenoid coupling” strategy. dppp=1,3-bis(diphenylphosphanyl)propane, NBS=N-bromosuccinimide, LiHMDS= lithium hexamethyldisilazide, HMPA=hexamethyl phosphoramide. Scheme 1. Simple nonphotochemical route to helicene quinones by Katz and Liu.

Antonio Urbano

Papers

Recent Developments in the Synthesis of Helicene‐Like Molecules

Enantiopure sulfoxides: recent applications in asymmetric synthesis

N-Bromosuccinimide in Acetonitrile: A Mild and Regiospecific Nuclear Brominating Reagent for Methoxybenzenes and Naphthalenes

Oxidative De-aromatization of para-Alkyl Phenols into para-Peroxyquinols and para-Quinols Mediated by Oxone as a Source of Singlet Oxygen

Neuere Entwicklungen in der Synthese Helicen‐artiger Moleküle