Addition reactions overview

Less common addition reactions such as the bromination of trifhioromethyl-substi-tuted butatrienes [30] or the reaction of tetrafluoroallene with boron trifluoride have also been reported [283]. Especially the interaction of phosphorylated allenes with electrophiles was summarized in a review by Alabugin and Brel [8], whereas Smadja [284] published a more general overview about the electrophilic addition to allenic derivatives. 

Having collected much information, several investigators, notably Valk et al. [21] and Day and Wiles [25], were able to suggest photolysis mechanisms to account for their observations. Summaries of these have been published in review works [27], Grossetete et al. [11] have also published a set of reaction schemes for the PECT copolymer. We will now present an overview set of schemes which combine all of the possible reactions they reported and some additional reactions to more fully account for products from both photolysis and photo-oxidation reactions. Evidence for each of the paths will be discussed, along with some speculation about other products that should reasonably accompany these paths but that have not yet been reported. 

The addition of organolithiums to polarised C=X bonds is one of the most widely used ways of making C-C bonds, and (excepting some unusual intramolecular cases) will not be discussed in this book other than to say it is a reliable and successful reaction. With a few exceptions,1 3 stereoselectivity is not a general feature of organolithium addition reactions to C=0 n bonds. Much of this chapter will concern controlled addition of organolithiums to C=C 7i bonds after an overview of carbolithiation, we shall review the development of intramolecular carbolithiation, or anionic cyclisation. 

The extensive use of Cp -titanium complexes in the development of organic synthetic methodology is beyond the scope of this chapter. We include here some examples of the various reaction types in which titanium(iv) derivatives are used as reagents in organic synthesis, although no attempt has been made to cover this subject comprehensively. Section 4.05.8 covers additionally an overview of the applications of titanium complexes in stoichiometric and catalytic organic reactions. 

This chapter has attempted to present a thorough overview of alkaloid syntheses in which free-radical cyclizations have played a pivotal role. It is not meant to be a comprehensive review, but focusses on syntheses in which nitrogen plays a clear role in the cyclization process, either as an attenuator of radical reactivity (Sections 4,1.2 and 4.1.3), a tether (Section 4.1.4), or a radical acceptor (Section 4.1.5). Several other notable alkaloids syntheses have been reported in which carbocyclizations play the pivotal role and introduction of nitrogen is secondary, for example Sha s syntheses of (-)-dendrobine [76] and (-t-)-paniculatine [77], and Clive s synthesis of (+)-fredericamycin [78]. Syntheses in which nitrogen-centered radicals play a critical role are also known, such as the Zard synthesis of (—)-dendrobine [79]. My apologies to these authors for not elaborating on their fine contributions, to authors who have nicely used intermolecular radical addition reactions in alkaloid synthesis, and to others whose contributions may have escaped my attention. 

A theoretical description of the addition reaction, based on Troe s formulation of unimolecular reaction rate theory, has been constructed to address the question of the consistency of our results and the earlier low temperature measurements. These calculations show a dramatic combined temperature and pressure dependence of this rate constant which must be included when this reaction is incorporated into models of combustion chemistry. These results illustrate the need to combine individual experimental data with a theoretical overview in order to obtain a description valid over the range of T and P likely encountered in combustion systems. 

Table 1 gives an overview of addition reactions to unsaturated compounds. C-C coupling reactions such as Heck, Suzuki and Sonogashira coupling are described in Section 7.4.2. 

Addition and elimination reactions are one of the most important classes of reactions in organic synthesis because they serve as powerful tools for the construction of a variety of organic structures. This chapter provides an overview of elimination and addition reactions using microflow reactors. 

This chapter will discuss the utility of alkenyl and arylboronic acids and their derivatives in addition reactions with C=N functionality. Since there have been no major reviews of this area [6], a detailed overview of the field will be given, covering the period 1993 to early 2004. 

Several comprehensive reviews of photochemical SET reactions of amines are available, as are more specialized reviews of the reactions of amines with specific classes of excited states. - These include reviews of the photochemical reactions of amines with arenes and iminium ions, which appeared in the first edition of this Handbook. The present article provides an overview of the photochemical addition reactions of amines with alkenes. Detailed information about the mechanisms and dynamics of these reactions is provided in the original literature and the comprehensive reviews. 

Figure 23 Overview of possible addition reactions for the functionalization of the nanotube sidewall. Adapted with permission from Balasubramanian, K. ...

After 15 years have passed since the first publication on the metal complex-catalyzed addition of /f-phosphonate, almost all possible variations in the H—P(0) bond addition reactions have already been published. After the overview of the progress since some 8 years ago herein summarized, the remaining area for future research has become clear and can be summarized as follows ... 

Other group-charactenstic in situ prechromatographic reactions have been described in addition to the ones discussed above They all serve to improve the charactenzation of the substances concerned and the selectivity of the subsequent chromatography Table 17 provides an overview... 

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