From organometallics with

The reaction of carbon nucleophiles derived from organometallics with carboxylic acid derivatives follows closely the reactions we have already encountered in Sections 6.3.2 and 7.6.2. Organometallics... 

Further reactions of allyl organometallics with a-alkoxyaldimines 1, prepared from (S)-2-(methoxymcthoxy)propionaldehyde and (R)- and (S)-l-phenylethylamine, illuminate the difference in the influence of the nitrogen chiral auxiliary and the x-alkoxy center7. 

Figure 2.7 The solid-state31P NM R spectrum of RhCl(PPh3)j. (Reprinted with permission from Organometallics, 1992,11, 3240. Copyright (1992) American Chemical Society.)...

Aylett, B. J., and Tannahill, A. A., Chemical Vapour Deposition of Metal Silicides from Organometallic Compounds with Silicon-Metal Bonds, SIRA Int. Seminar on Thin Film Preparation and Processing Technolgy, Brighton, UK (March 1985)... 

Metal clusters on supports are typically synthesized from organometallic precursors and often from metal carbonyls, as follows (1) The precursor metal cluster may be deposited onto a support surface from solution or (2) a mononuclear metal complex may react with the support to form an adsorbed metal complex that is treated to convert it into an adsorbed metal carbonyl cluster or (3) a mononuclear metal complex precursor may react with the support in a single reaction to form a metal carbonyl cluster bonded to the support. In a subsequent synthesis step, metal carbonyl clusters on a support may be treated to remove the carbonyl ligands, because these occupy bonding positions that limit the catalytic activity. 

Figure 2 Crystal structures of the monovalent hydrido (4c) (left) and ethylene (4d) (right) complexes of z-Pr-5-MeTp (reproduced with permission of the American Chemical Society from Organometallics, 1999, 18,...

The predominance of organometallics with electron-withdrawing substituents (Sections III,A-D, and F) can partly be attributed to the promotion of some mechanisms by these substituents [e.g., Eqs. (4), (6), and (15)] (Section II,B). This imposes limitations, as a number of polyha-logenobenzoates, notably 2,3,4,5-tetrafluorobenzoates, have insufficient electron-withdrawing capacity for decarboxylation to occur (Section III,D). Although mechanisms promoted by electron-donating substituents can be formulated (Section II,B), there is little evidence yet for their operation apart from classic electrophilic aromatic decarboxylation [Eq. (12)] (see also Section III,E). 

Scheme 19 Proposed mechanism for the reaction of Sml2 with [Me2Si(C5H4)(C2BioHii)]. Reproduced by permission of the American Chemical Society from Organometallics 2000, 79, 1391.

As well as alkenylstannanes [106-108], other classes such as a-heteroatom-substituted alkyltributylstannanes [109] and, more importantly, allylic stannanes [110, 111] also undergo these Sn-Cu transmetalations. Otherwise difficult to prepare, allylic copper reagents may, however, be obtained by treatment of allylic stannanes (produced in turn from organolithium, magnesium, or zinc organometallics) with Me2CuLi LiCN. They enter into cross-coupling reactions with alkyl bromides [110] or vinyl triflates (Scheme 2.52) [111]. 

Deterioration of catalysts is an everyday experience from working with highly water-sensitive compounds in insufficiently dried solvents, but in the reactions within aqueous organometallic catalysis water is either innocuous (this is the case with [RhCl(PPh3)3]) or may even be advantageous, taking an active part in the formation of catalytically active species. 

There are many examples of organometallic compounds containing oxygen atoms as ligands an appreciable number of these resulted from reactions with O2. Early work has been reviewed by Bottomley and Sutin [ 17]. Thus we concentrate on more recent reports, and those of particular interest. 

Chloropyrroles have been prepared from organometallic derivatives indeed, the first synthesis of 2-chloropyrrole was from the reaction of pyrrolylmagnesium bromide with chlorine at -50°C [62MI2 77MU], and lithium derivatives with NCS have also been used (84MI3). 

In the most general sense, any anion radical produced by reduction with a metal, or by electrolytic reduction in the presence of a metallic counterion could be considered an organometallic anion radical. Any review based on such a definition would be monumental. To achieve a manageable volume of material, with a content suitable to the context of this series, we have limited this chapter to anion radicals produced from organometallic compounds. Anion radicals for which the metal is present solely as the reducing agent or counterion have, for the most part, been excluded. 

The ff-adducts are obtained with the hydride ion under conditions similar to those derived from organometallic reagents and may therefore involve strong association or covalent bonding with the metal ions in much the same way (see initial statement regarding structural formulas in Section II, D,2,a). 

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