Selective organic synthesis

Yamamoto H., Yanagisawa A., Ishihara K., Salto S. Designer Lewis Adds for Selective Organic Synthesis Pure Appl. Chem. 1998 70 1507-1512 Keywords Lewis-acid reagents... 

Photocatalysis is a fundamental feature of life processes on our planet [1] (it provides photosynthesis in plants and bacteria) and of the chemistry of its atmosphere [2]. Work is under way to develop photocatalytic technologies for abatement of environmental problems [3,4]. Photocatalysis is anticipated to become in the coming years important also for selective organic synthesis [4]. In a more distant future thermal catalytic processes induced by heating with solcir radiation, together with photocatalytic processes may become important for environmentally friendly technologies of solar energy utilization [5-9]. 

Ruthenium carbonyl complexes have been shown to catalyze a number of car-bonylation processes. The ruthenium-catalyzed intramolecular Pauson-Khand reaction was found to proceed in the presence of Ru3(CO)12 (Eq. 105) [165,166]. The reaction is a valuable tool for selective organic synthesis. 

Mediators with lower standard potential (Ce, Mn, sometimes Co) are mainly used in selective organic synthesis (1, 2). We chose Ce4+ (E = 1.61 V) as oxidation agent to avoid total combustion to C02 and because of the large solubility of its salts in aqueous solutions. 

Lindberg, T., Ed., Academic Press, New York, 1984, vol. I 1989, vol 2. see also Fleming, I. Selected Organic Synthesis. A Guidebook for Organic Chemists, Wiley, New York, 1973. 

Barron, A. R. In his lecture during International Symposium of Lewis Acid Catalysis for Selective Organic Synthesis, Nagoya, 1999. 

It must be mentioned that the most versatile and representative organosilicon Lewis acid is undoubtedly trimethylsilyl triflate (la), the structure of which reflects the inertness of tetraalkylsilanes for Lewis basic substrates and the requirement of a counter-anion to increase the electrophilicity of the silicon center. Noyori s pioneering studies on the reactions of trimethylsilyl triflate not only provided a general outline for stoichiometric transformations, but also inspired an extraordinary number of subsequent studies of the catalytic use of Lewis acids in selective organic synthesis. 

The first observation of penta- and hexaeoordinate silicon compounds was reported at the beginning of the 19th century by Gay-Lussac [87] and Davy [88], Subsequent investigation of hypercoordination in silicon compounds stimulated widespread use of nucleophilic activation and catalysis in the application of organosilicon compounds as reactive species in organic synthesis. Synthetic application for silicon-fluorine bond formation can be found in several reviews over the last two decades, and this section focuses on recent advances in the use of hypervalent organosilicon compounds in selective organic synthesis, in particular, selective carbon-carbon bond formation [89]. 

Both Sml2 and Cp2Sm have unique characteristics which lend themselves to selective organic synthesis, and their application to a variety of problems in formal C— X ir-bond addition reactions is outlined below. 

The title reaction represents the decomposition of arenesulfonylhydrazones with alkyllithium reagents to furnish unrearranged, less-substituted alkenes almost exclusively. The in situ generated alkenyllithium reagents can be further elaborated by reaction with an electrophile. Since the electrophile can be easily varied, the Shapiro reaction p>ermits the convenient transformation of a ketone into a single substituted alkene in a synthetically useful way. This section will highlight the versatility of this reaction in selective organic synthesis. 

Barluenga, J. Recent advances in selective organic synthesis mediated by transition metal complexes. Pure Appt. Chem. 1999, 71,1385-1391. 

A comprehensive review on lanthanocene catalysts in selective organic synthesis has been published by Molander and Romero.37 Petrov et al,39 have reviewed the synthesis, structure, and reactivity organolanthanides RLnX (R = alkyl, aryl X = halogen) and lanthanide compounds with aromatic hydrocarbon dianions. 

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