Organometallic halides

Fig. 13 Ni-catalyzed three-component reactions of alkyl halides, organometallic reagents and arylalkynes or enynes, respectively...

Organometallic or mixed halide-organometallic diketonates of Si, Ge, Sn, Pb, Ti, Zr, Sb can be synthesized in the presence of base (sodium methoxide, pyridine, triethylamine, ammonia) (Equations (15) and (16)) ... 

Bianchini G, Giambastiani IG, Rios A et al (2007) Synthesis of a new polydentate ligand obtained by coupling 2,6-bis(amino)pyridine and (imino)pyridine moieties and its use in ethylene oligomerisation in conjunction with iron(II) and cobalt(II) bis-halides. Organometallics 26 5066-5078... 

Datta, A., Ebert, K. and Plenio, H. (2003) Nanoflltration for homogeneous catalysis separation soluble polymer-supported palladium catalysts for Heck, Sonogashira, and Suzuki coupling of aryl halides. Organometallics, 22, 4685-91. 

Homogeneous Catalysis Lanthanide Halides Organometallic Chemistry Fundamental Properties Tetravalent Chemisiry Inoiganic Tetravalent Chemistry Organometallic The Divalent State in Solid Rare Earth Metal Halides The Electronic Structure of the Lanthanides. 

Lefevre G, Franc G, Adamo C, Jutand A, Ciofini I (2012) Influence of the formation of the halogen bond ArX.N on the mechanism of diketonate ligated copper-catalyzed amination of aromatic halides. Organometallics 31 914—920... 

When reacting with allylic halides, organometallics tend to undergo Sa 2 and S/v2 processes concomitantly. Allylic amines and allylic ethers or acetals generally follow the latter mode provided that metalation is precluded. ... 

In Grignard reactions, Mg(0) metal reacts with organic halides of. sp carbons (alkyl halides) more easily than halides of sp carbons (aryl and alkenyl halides). On the other hand. Pd(0) complexes react more easily with halides of carbons. In other words, alkenyl and aryl halides undergo facile oxidative additions to Pd(0) to form complexes 1 which have a Pd—C tr-bond as an initial step. Then mainly two transformations of these intermediate complexes are possible insertion and transmetallation. Unsaturated compounds such as alkenes. conjugated dienes, alkynes, and CO insert into the Pd—C bond. The final step of the reactions is reductive elimination or elimination of /J-hydro-gen. At the same time, the Pd(0) catalytic species is regenerated to start a new catalytic cycle. The transmetallation takes place with organometallic compounds of Li, Mg, Zn, B, Al, Sn, Si, Hg, etc., and the reaction terminates by reductive elimination. 

Formation of ketones. Ketones can be prepared by the carbonylation of halides and pseudo-halides in the presence of various organometallic compounds of Zn, B, Al, Sn, Si, and Hg, and other carbon nucleophiles, which attack acylpalladium intermediates (transmetallation and reductive elimination). 

Acyl halides react with organometallic reagents without catalysts, but sometimes the Pd-catalyzed reactions give higher yields and selectivity than the Lincatalyzed reactions. Acyl halides react with Pd(0) to form the acylpalladium complexes 846, which undergo facile transmetallation. 

The properties of organometallic compounds are much different from those of the other classes we have studied to this point Most important many organometallic com pounds are powerful sources of nucleophilic carbon something that makes them espe cially valuable to the synthetic organic chemist For example the preparation of alkynes by the reaction of sodium acetylide with alkyl halides (Section 9 6) depends on the presence of a negatively charged nucleophilic carbon m acetylide ion... 

Before we describe the applications of organometallic reagents to organic synthesis let us examine their preparation Organolithium compounds and other Group I organometal he compounds are prepared by the reaction of an alkyl halide with the appropriate metal... 

Organometallic compounds of copper were known for a long time before their versatil ity in synthetic organic chemistry was fully appreciated The most useful ones are the lithium dialkylcuprates which result when a copper(I) halide reacts with two equivalents of an alkyllithium in diethyl ether or tetrahydrofuran... 

Grignard reagents react with ethylene oxide to yield primary alcohols containing two more carbon atoms than the alkyl halide from which the organometallic compound was prepared... 

The fundamental Ziegler-Natta recipe consists of two components the halide or some other compound of a transition metal from among the group IVB to VIIIB elements and an organometallic compound of a representative metal from groups lA to IIIA. Some of the transition metal compounds that have been... 

The bimetallic mechanism is illustrated in Fig. 7.13b the bimetallic active center is the distinguishing feature of this mechanism. The precise distribution of halides and alkyls is not spelled out because of the exchanges described by reaction (7.Q). An alkyl bridge is assumed based on observations of other organometallic compounds. The pi coordination of the olefin with the titanium is followed by insertion of the monomer into the bridge to propagate the reaction. 

Alkyl and arylboranes are obtained (35) from BF using the appropriate Grignard reagent, alkylalurninum halide, or zinc alkyl, using diethyl ether as the solvent (see also Organometallics) ... 

Cross coupling of organometallics with organic halides catalyzed by non (ill). 

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