Angewandte Chemie International Edition

Renaud, Philippe; Gerster, Michèle

doi: 10.1002/(SICI)1521-3773(19981016)37:19<2562::AID-ANIE2562>3.0.CO;2-Dpmid: 29711628

The neglect of free radicals over the past few years has been overcome, and they are no longer only considered as interesting reactive intermediates with limited synthetic potential. New opportunities are opened up by performing radical reactions in the presence of Lewis acids. Rate enhancement of radical addition to olefins as well as stereochemical control of such reactions can be achieved in a unique manner. Recent examples of enantioselective radical reactions and perspectives for applications in catalysis are discussed.

Lucet, Denis; Le Gall, Thierry; Mioskowski, Charles

doi: 10.1002/(SICI)1521-3773(19981016)37:19<2580::AID-ANIE2580>3.0.CO;2-Lpmid: 29711625

Especially in the field of enantioselective synthesis, vicinal diamines (1,2‐diamines) 1 and compounds easily prepared from them—such as 1,2‐bisimines, 1,2‐diamides, or imidazolidin‐2‐ones—are widely used by organic chemists. Various strategies have been developed to produce these compounds selectively. Many natural products and medicinal agents also contain a 1,2‐diamino unit.

Pietruszka, Jörg

doi: 10.1002/(SICI)1521-3773(19981016)37:19<2629::AID-ANIE2629>3.0.CO;2-Apmid: 29711630

Fascinating structures and stunning cytotoxicities characterize the altohyrtins A–C, the spongistatins 1–9, and cynachyrolide A. The first total syntheses reported by the groups from Evans and Kishi could unequivocally prove the structure of the extremely potent inhibitors of the tubulin polymerization.

Tuczek, Felix; Lehnert, Nicolai

doi: 10.1002/(SICI)1521-3773(19981016)37:19<2636::AID-ANIE2636>3.0.CO;2-Qpmid: 29711627

The production of ammonia from atmospheric dinitrogen at room temperature and ambient pressure in analogy to nature is a long‐term goal for coordination chemists. Novel reactions of N2‐containing transition metal complexes with H2, the first side‐on N2‐bridged structure of an actinide complex, and an interesting variation of synthetic N2 fixation are the key points addressed in this contribution. The results are related to the known chemistry of N2 complexes, and their significance is discussed with respect to enzymatic N2 fixation.

Fenske, Dieter; Zhu, Nianyong; Langetepe, Timo

doi: 10.1002/(SICI)1521-3773(19981016)37:19<2639::AID-ANIE2639>3.0.CO;2-8pmid: 29711600

A significant extension of the class of AgSe clusters is achieved with the synthesis of the title compounds. This confirms the concept that attaching organic ligands to the outer surface of the cluster hinders the formation of stable binary selenides. The protecting phosphane ligands have a great influence on the structure of the cluster formed. The structure of (Ag90Se38(SetBu)14(PEt3)22) is shown here (the tBu and Et groups are omitted for the sake of clarity).

Holzwarth, Arnold; Schmidt, Hans‐Werner; Maier, Wilhelm F.

doi: 10.1002/(SICI)1521-3773(19981016)37:19<2644::AID-ANIE2644>3.0.CO;2-#pmid: 29711616

Only about 200 μg of catalyst are required to identify the catalytically active materials on a combinatorial library of heterogeneous catalysts by IR thermography. The procedure is highly sensitive, and temperature differences arising from catalytic activity of hydrogenations and oxidations have been reliably detected down to 0.1 K.

Reetz, Manfred T.; Becker, Michael H.; Kühling, Klaus M.; Holzwarth, Arnold

doi: 10.1002/(SICI)1521-3773(19981016)37:19<2647::AID-ANIE2647>3.0.CO;2-Ipmid: 29711629

Simple monitoring of lipase‐ and transition metal catalyzed asymmetric esterifications (Eq. (1)) and opening of epoxides (Eq. (2)) can be achieved by IR thermography. Thus, a new method is available for screening of enantioselectivity in catalytic reactions.

Yang, Yu; Pinkas, Jiri; Schäfer, Martina; Roesky, Herbert W.

doi: 10.1002/(SICI)1521-3773(19981016)37:19<2650::AID-ANIE2650>3.0.CO;2-Lpmid: 29711621

Two tricyclic capped six‐rings (C6R), a double four‐ring (D4R), and an Al(μ‐F)2Al unit are among the structural features of 1 (see picture for structure) that are closely related to motifs found in layered and three‐dimensional alumino‐ and gallophosphates. Several reactive centers can render 1 a viable precursor for the synthesis of microporous aluminophosphates.

Terao, Jun; Torii, Kazushi; Saito, Koyu; Kambe, Nobuaki; Baba, Akio; Sonoda, Noboru

doi: 10.1002/(SICI)1521-3773(19981016)37:19<2653::AID-ANIE2653>3.0.CO;2-3pmid: 29711633

Vinylsilanes and/or allylsilanes are formed upon silylation of terminal alkenes with R3′SiCl in the presence of a Grignard reagent and a catalytic amount of (Cp2ZrCl2) (Eq. (a)). The reaction also proceeds under mild conditions when silylsulfides (X=SPh), silylselenides (X=SePh), and silyltellurides (X=TePh) are used in place of chlorosilanes (X=Cl). R″=alkyl, aryl, alkylsilyl; R′=Me, Et, nPr; R=CH2R″, aryl, H.

Abrahams, Brendan F.; Jackson, Patricia A.; Robson, Richard

doi: 10.1002/(SICI)1521-3773(19981016)37:19<2656::AID-ANIE2656>3.0.CO;2-Mpmid: 29711608

Framework integrity is retained when water molecules replace the nitromethane molecules in the coordination polymer (Ag(hat)ClO4)⋅2 CH3NO2 (see picture for structure), which are arranged in a helical fashion within the chiral micropores of the three‐dimensional (Ag(hat)+)n network with a (10,3)‐a topology. Remarkably, this is also the case after subsequent displacement of the water by nitromethane molecules. hat=1,4,5,8,9,12‐hexaazatriphenylene.