Promoter organization

N,N,N, N -tetramethyl-l,8,-naph-thalenediamiDe M.P. 51 C. A remarkably strong mono-acidic base (pKg 12-3) which is almost completely non-nucleophilic and valuable for promoting organic elimination reactions (e.g. of alkyl halides to alkenes) without substitution. 

OrganothaHium(III) derivatives can be classified into three types R3TI, R2TIX, and RTIX2. The trialkyl derivatives are reactive, unstable compounds, whereas the dialkyl derivatives are among the most stable and least reactive organometaHic compounds. The monoalkyl compounds are rather unstable and often caimot be isolated. They are important intermediates in some Tl(III)-promoted organic reactions. 

It is believed that clay minerals promote organic reactions via an acid catalysis [2a]. They are often activated by doping with transition metals to enrich the number of Lewis-acid sites by cationic exchange [4]. Alternative radical pathways have also been proposed [5] in agreement with the observation that clay-catalyzed Diels-Alder reactions are accelerated in the presence of radical sources [6], Montmorillonite K-10 doped with Fe(III) efficiently catalyzes the Diels-Alder reaction of cyclopentadiene (1) with methyl vinyl ketone at room temperature [7] (Table 4.1). In water the diastereoselectivity is higher than in organic media in the absence of clay the cycloaddition proceeds at a much slower rate. 

In addition to complex-formation, the interaction of transition-metal atoms with organic substrates at low temperatures can result in rearrangement of the organic moiety without complexation. Two such reactions have already been briefly mentioned, namely, the polymerization of hexafluoro-2-butyne by Ge and Sn atoms (72) and the polymerization of styrene by Cr atoms (i 1). In this section we shall briefly summarize some of these transition-metal-atom-promoted, organic rearrangements. 

The interest in mineral-promoted organic reactions stems from the need to understand the fate of pesticides in soils and pollutants in sedimentary environments (8), petrogenesis (20-27), humification (19, 28, 29), the origin and evolution of life (1, 30), the use of clays as catalysts in industrial processes (31-37), in pharmaceutical applications (3), and as pigments and fillers in paper, plastic, and rubber (37). 

N.E. Leadbeater, R.J. Smith and T.M. Barnard, Using in situ Raman monitoring as a tool for rapid optimisation and scale-up of microwave-promoted organic synthesis Esterification as an example, Org. Biomol. Chem., 5, 822-825 (2007). 

Organic Reactions in Micro-Organized Media—Why and How Water-Promoted Organic Reactions The design of green oxidants Water as a solvent for chemical reactions Water as a benign solvent for chemical syntheses... 

In listing the ways in which metal ions may promote organic reactions, the requirement that the metal ion be suitably positioned within the substrate molecule was emphasized. Specific complexation or chelation of the metal ion with the substrate appears to be an absolute requirement of metal ion catalysis. In many cases chelation appears to be the rule, which usually means that the substrate must contain a donor atom in addition to the reactive center of the molecule with which the metal ion also complexes, or must contain two donor atoms in addition to the reactive center. Many attempts have been made to correlate the effectiveness of catalysis by a series of metal ions with the relative formation constants of the complexes. Such correlations have been successful in a number of reactions, but unsuccessful in others. In the successful correlations the complex chosen for the correlation closely approximates the transition state of the reaction. This indicates that the metal ion complex must stabilize the transition state of the reaction in order to assist the reaction effectively, and that metal ion complex formation in the ground state can have an effect exactly opposite to that of catalysis, since in such a case the ground state becomes stabilized. 

Lewis acids are important catalysts for promoting organic reactions because they coordinate heteroatoms of functional groups. Lewis acids interact with carbonyl oxygen in its plane in either syn or anti fashion 248). Such perturbation of acceptor molecules lowers the LUMO level... 

Majetich, G. and Hicks, R., The use of microwave heating to promote organic reactions, /. Microwave Power... 

Lubineau, A., Auge, J. and Queneau, Y., Water-promoted organic reactions, Synthesis, 1994, 741. 

Upham BL, Guzvic M, Scott J, Carbone JM, Blaha L, Coe C, Li LL, Rummel AM, Trosko JE. 2007. Inhibition of gap junctional intercellular communication and activation of mitogen-activated protein kinase by tumor-promoting organic peroxides and protection by resveratrol. Nutr Cancer 57 38-47. 

Although zwitterions are mainly considered for their novel ion conductive matrix in this chapter, they are being used as not only as solvents and catalysts for organic reactions [42] but also as organogelators [43]. Zwitterions have been screened as solvent/catalysts for several classical acid-promoted organic reactions such as the Fischer esterification, alcohol dehydrodimerization, and the pinacol/ benzopinacole rearrangement. The zwitterion containing an equimolar trifluoro-methane sulfonic acid is liquid at room temperature. Because they can work as solvent/catalysts, as shown in the reactions discussed in this chapter, zwitterionic liquids should open the door to a whole new area of applications. 

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