Alkenes organic reactions involving reactive

Reactions of Alkenes—An Overview Organic Reactions Involving Reactive Intermediates Electrophilic Additions Hydroboration-Oxidation Oxidation... 

The carbon-carbon bond forming step of the Prins reaction, the reaction of an alkene with a carbonyl group (1) - (2), is, in one sense, the most fundamental reaction of synthetic organic chemistry at one extreme it is the base-catalyzed aldol reaction, where the alkene component is an enolate ion and the carbonyl group is unprotonated, and at the other extreme it is the Friedel-Crafts reaction. It is a paradigm for a fast organic reaction both bonds involved in the key step are iT-bonds, which are simultaneously more reactive than o-bonds and more susceptible to modification in reactivity by the presence or absence of substituents on either or both components. It is no wonder that, in one form or another, it is the most frequently used of all carbon-carbon bond forming reactions. 

For this review we limit the definition of G-F bond activation at transition metal centers to reactions involving cleavage of C-F bonds mediated by transition metals. The majority of such reactions involve a change in the primary coordination sphere of the metal. Nevertheless, the definition allows for enhancement of reactivity of G-F bonds even if the immediate coordination sphere of the metal is unchanged. Section 1.26.1 of our review sets out the principal modes of coordination of fluorinated molecules to transition metal centers and the principal pathways for C-F bond activation with one or two examples for each type. Section 1.26.2 provides a moderately comprehensive set of examples of intermolecular G-F bond activation organized by aromatic, alkene, and aliphatic C-F bonds and for the period 1997-2005. Section 1.26.3 follows the same pattern but for intramolecular G-F activation. 

Another general process involves the reaction of Pd(0) species with halides or sulfonates by oxidative addition, generating reactive intermediates having the organic group attached to Pd(II) by a ct bond. The oxidative addition reaction is very useful for aryl and alkenyl halides, but the products from saturated alkyl halides often decompose by (3-elimination. The a-bonded species formed by oxidative addition can react with alkenes and other unsaturated compounds to form new carbon-carbon bonds. The... 

Allenes are versatile synthetic precursors in organic chemistry and the synthesis of many natural products involves the use of allenic compounds [27]. However, they have received much less attention than alkenes or alkynes for transition metal catalyzed reactions. The explanation lies in the problems of selectivity that these substrates display as a result of their reactivity and their inherent chirality [28]. 

The results described in this article establish that the stilbenes are among the most versatile of organic reactants in bimolecular photochemical reactions. Only triplet cyclo-alkenones can rival the ability of It to dimerize, form [2+2] adducts with both electron-rich and electron-poor alkenes, and form acyclic adducts with amines, heterocycles, and noncon-jugated dienes. All of the known bimolecular photochemical reactions of excited stilbenes involve It as the reactive excited state. The failure of - -c, and 3C to undergo bi-... 

The oxidation of substituted /3-benzoylpropionic acids by PFC follows the Hammett relation with a negative reaction constant. A possible mechanism for the oxidation has been discussed.5 The oxidation of maleic, fumaric, crotonic, and cinnamic acids by PCC is of first order with respect to PCC and the acid. The oxidation rate in 19 organic solvents has been analysed by Kamlet s and Swain s multiparametric equations. A mechanism involving a three-centre transition state has been postulated.6 The relative reactivity of bishomoallylic tertiary alcohols toward PCC, to yield substituted THF products via the tethered chromate ester, is dependent only on the number of alkyl groups. This observation suggests a symmetrical transition state in this intramolecular Cr(VI)-alkene reaction.7 Mechanisms have been proposed for the oxidation of 2-nitrobenzaldehyde with PBC8 and of crotonaldehyde with tetraethylammonium chlorochromate.9... 

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