Cross-coupling reactions alkenes

Heck reaction, palladium-catalyzed cross-coupling reactions between organohalides or triflates with olefins (72JOC2320), can take place inter- or intra-molecularly. It is a powerful carbon-carbon bond forming reaction for the preparation of alkenyl- and aryl-substituted alkenes in which only a catalytic amount of a palladium(O) complex is required. 

A cross-coupling reactions of terminal alkynes with terminal alkenes 32 supported on Merrifield-resin (Scheme 4.5) in the presence of Grubs ruthenium initiator [Cl2(PCy3)2Ru = CHPh] provided efficient access to supported 1,3-dienes 33 which were transformed into octahydrobenzazepinones 34 via MeAlCl2 catalyzed Diels-Alder reaction [27]. 

Over the last decade, the chemistry of the carbon-carbon triple bond has experienced a vigorous resurgence [1]. Whereas construction of alkyne-con-taining systems had previously been a laborious process, the advent of new synthetic methodology based on organotransition metal complexes has revolutionized the field [2]. Specifically, palladium-catalyzed cross-coupling reactions between alkyne sp-carbon atoms and sp -carbon atoms of arenes and alkenes have allowed for rapid assembly of relatively complex structures [3]. In particular, the preparation of alkyne-rich macrocycles, the subject of this report, has benefited enormously from these recent advances. For the purpose of this review, we Emit the discussion to cychc systems which contain benzene and acetylene moieties only, henceforth referred to as phenylacetylene and phenyldiacetylene macrocycles (PAMs and PDMs, respectively). Not only have a wide... 

Iron-catalyzed C(sp )-C(sp ) bond-forming cross-coupling reactions of alcohols with alkenes has been reported by Tu and coworkers in 2009 [109]. Reactions of primary alcohols with various alkenes in the presence of a catalytic amount of FeCls in 1,2-dichloroethane afford the desired secondary alcohols as the crosscoupling products in moderate to good yields (Scheme 33). Iron sources such as... 

The hydrosi(ly)lations of alkenes and alkynes are very important catalytic processes for the synthesis of alkyl- and alkenyl-silanes, respectively, which can be further transformed into aldehydes, ketones or alcohols by estabhshed stoichiometric organic transformations, or used as nucleophiles in cross-coupling reactions. Hydrosilylation is also used for the derivatisation of Si containing polymers. The drawbacks of the most widespread hydrosilylation catalysts [the Speier s system, H PtCl/PrOH, and Karstedt s complex [Pt2(divinyl-disiloxane)3] include the formation of side-products, in addition to the desired anh-Markovnikov Si-H addition product. In the hydrosilylation of alkynes, formation of di-silanes (by competing further reaction of the product alkenyl-silane) and of geometrical isomers (a-isomer from the Markovnikov addition and Z-p and -P from the anh-Markovnikov addition. Scheme 2.6) are also possible. 

Transition metal-catalyzed transformations are of major importance in synthetic organic chemistry [1], This reflects also the increasing number of domino processes starting with such a reaction. In particular, Pd-catalyzed domino transformations have seen an astounding development over the past years with the Heck reaction [2] - the Pd-catalyzed transformation of aryl halides or triflates as well as of alkenyl halides or triflates with alkenes or alkynes - being used most often. This has been combined with another Heck reaction or a cross-coupling reaction [3] such as Suzuki, Stille, and Sonogashira reactions. Moreover, several examples have been published with a Tsuji-Trost reaction [lb, 4], a carbonylation, a pericyclic or an aldol reaction as the second step. 

Using Pd-mediated cross-coupling reactions, such as Suzuki, Heck, and Sonoga-shira- Hagihara reaction, researchers efficiently constructed a library of 151 coumarin derivatives from eight 3-bromocoumarins cross-coupled with ten aryl/heteroaryl boronic acids, ten alkenes, and ten alkynes (Fig. 4). 

Since one of the substrates is a cyclic alkene there is now the possibility of ring-opening metathesis polymerisation (ROMP) occurring which would result in the formation of polymeric products 34 (n >1). Since polymer synthesis is outside the scope of this review, only alkene cross-metathesis reactions resulting in the formation of monomeric cross-coupled products (for example 30) will be discussed here. 

The transition metal cross-couplings of allenes described here offer practical solutions for the modification of 1,2-dienes and access to the preparation of highly functionalized 1,3-dienes, alkynes and alkenes, which are often not easily accessible in a regio- and stereoselective manner by classical methods. Some of the prepared alkynes or functionalized allenes serve as important intermediates in syntheses of natural products, biologically active compounds, e.g. enynes and enyne-allenes, and new materials. It can be predicted that further synthetic efforts will surely be focused on new applications of allenes in transition metal-catalyzed cross-coupling reactions. 

Palladium salts will attack C-H bonds in functionalised aromatics such as acetoaniline to form palladium-carbon bonds that subsequently undergo insertion of alkenes [31], (3-Hydride elimination gave styryl derivatives and palladium hydride, which requires re-oxidation of palladium by benzoquinone. The reaction can be regarded as a combined Murai reaction (C-H activation, if electrophilic) and a Heck reaction (arylalkene formation), notably without the production of salts as the cross-coupling reactions do. An example is shown in Figure 19.15. 

Pd(II)-catalysed cross-coupling reactions of aryl tellurides with alkenes... 

The cross-coupling reaction of diaryl tellurides with alkenes in MeOH in the presence of Pd " catalyst, EtjN and AgOAc as oxidant, gives the corresponding aryl-substituted (Z)-aUcenes in good yields. ... 

Braese, S. de Meijere, A. Gross-Coupling of Organic Halides with Alkenes the Heck Reaction. In Metal-Catalyzed Cross-Coupling Reactions, 2nd ed. de Meijere, A., Diederich, F., Eds. Wiley-VCH Weinheim, 2004 pp 217-315. 

Despite its apparent noble character, gold catalysts have been recently found to be active in many homogeneous and heterogeneous catalytic processes such as oxidation reactions, nucleophilic additions, cross-coupling reactions, and alkene and imine hydrogenations (69—71). Corma and co-workers showed that Au... 

A number of methods for the preparation of vinyl and allyl sulfones are available [1U9, 110], and the syntheses of vinyl sulfones from alkenes has been reviewed [116]. A simple one-step procedure of wide applicability makes use of a palladium-catalysed cross-coupling reaction between aryl and alkyl sulfonyl chlorides and substituted vinyl and allyl stannanes... 

Cross-coupling reactions of alkenylsilicates 114 with aryl or vinyl halides or triflates are catalyzed by a palladium complex to give the corresponding alkenes (equation 92)173. 

Alkenylboron compounds cyclopropanations, 9, 181 haloetherification, 9, 182 hydrogenation and epoxidation, 9, 182 metal-catalyzed reactions, 9, 183 metallic reagent additions, 9, 182 via radical addition reactions, 9, 183 5-Alkenylboron compounds, cross-coupling reactions, 9, 208 Alkenyl complexes with cobalt, 7, 51 with copper, 2, 160, 2, 174 with Cp Re(CO) (alkene)3 , 5, 915-916 with dicarbonyl(cyclopentadienyl)hydridoirons, 6, 175 with gold, 2, 255... 

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