Carbonyls, metal Reactions

The carbonyl addition reactions of benzylmetals, compared to the allylic counterparts, have found few applications in stereoselective synthesis, apparently for the following reasons The carbonyl addition of alkali metal salts (M = Li, Na, K, Cs) of benzyl anions, with few exceptions, usually proceeds with low levels of simple diastereoselectivity affording mixtures of syn- or <7 / -diastereomers (see Section 1.3.2.3.1.). 

Thus, the allyllithium, -sodium or -potassium derivatives are the ones which are most easily generated (Section D.1.3.3.3.1.1.), but they are of limited value in stereoselective carbonyl addition reactions. Usually these reagents need to be tuned" in their reactivity by metal exchange prior to application in order to achieve high selectivities. 

I.3.3.3.I.2. Stereoselective Carbonyl Addition Reactions of Allyl Alkali Metals... 

The reaction of the carbonyl metallates with chlorosilanes (Eq. (5)) can be considered to be a nucleophilic displacement at the silicon followed by NaCl elimination. Several arguments support this view First of all, strong dipolar aprotic... 

Kinetic studies on substitution reactions of carbonyl metal complexes. H. Werner, Angew. Chem., Int. Ed. Engl., 1968, 7,930-941 (106). 

Carbonyldlimidazolc, 78 Carbonyl-metal interactions, 74 Carbosiloxadienes, 452 Carboxy-ester interchange melt polyesterification, 113 Carboxy-ester interchange reactions, 62, 64, 69, 74... 

Another well-established metallization reaction is the decomposition of the carbonyl ... 

CO2MC] were obtained by metal exchange liom (he same ruthenium-dicobalt precursor and analogous functionalized (cyclopentadienyl)metal carbonyl Related reactions of the selenido-containing cluster RuCo2(/r rSe)... 

The lanthanides are congeners of the Group IIIA metals scandium and yttrium, with the +3 oxidation state usually being the most stable. These ions are strong oxyphilic Lewis acids and catalyze carbonyl addition reactions by a number of nucleophiles. Recent years have seen the development of synthetic procedures involving lanthanide metals, especially cerium.195 In the synthetic context, organocerium... 

The preparation of quinoline and tetrahydroquinoline derivatives from metal carbonyl-catalyzed reactions of Schiff bases with alkyl vinyl ethers in... 

Metal carbonyls undergo reactions with a great many compounds to produce mixed carbonyl complexes. A large number of these reactions involve the replacement of one or more carbonyl groups by a substitution reaction. Such reactions have also been studied kinetically in some cases. 

Alkali-immobile dye-releasing quinone compounds, 19 293-294 Alkali lignins, 15 19-20 Alkali manganate(VI) salts, 15 596 Alkali manganates(V), 15 592 Alkali-metal alkoxide catalysts, 10 491 Alkali-metal alkoxides, effects of, 14 252 Alkali-metal alkylstannonates, 24 824 Alkali-metal fluoroxenates, 17 329-330 Alkali-metal hydrides, 13 608 Alkali-metal hydroxides, carbonyl sulfide reaction with, 23 622 Alkali-metal metatungstates, 25 383 Alkali-metal perchlorates, 18 211 Alkali-metal peroxides, 16 393... 

For the purpose of carrying out carbonyl addition reactions, allylstannanes can be prepared in situ from metallic tin and an allyl halide (Barbier conditions),259 for example, Equation (93).260... 

Similar reactions can be carried out by using a tin(ll) compound rather than metallic tin.264-266 The allylstannanes are still easily handled but are much more reactive than the simple alkylstannanes, and their principal modes of reaction are summarized in Scheme 8. All these reactions, and particularly the carbonyl addition reactions (X=Y = R2C=0), are important in organic synthesis, and are covered in that respect in Volume 9. Only... 

As indicated in Chapter 8, the production of alkanes, as by-products, frequently accompanies the two-phase metal carbonyl promoted carbonylation of haloalkanes. In the case of the cobalt carbonyl mediated reactions, it has been assumed that both the reductive dehalogenation reactions and the carbonylation reactions proceed via a common initial nucleophilic substitution reaction and that a base-catalysed anionic (or radical) cleavage of the metal-alkyl bond is in competition with the carbonylation step [l]. Although such a mechanism is not entirely satisfactory, there is no evidence for any other intermediate metal carbonyl species. 

CONTENTS Introduction to Series An Editor s Foreword, Albert Padwa. Introduction, Timothy J. Mason. Historical Introduction to Sonochemistry, D. Bremner. The Nature of Sonochemical Reactions and Sonoluminescence, M.A. Mar-guli. Influence of Ultrasound on Reactions with Metals, 6. Pugin and A.T. Turner. Ultrasonically Promoted Carbonyl Addition Reactions, J.L. Luche. Effect of Ultrasonically Induced Cavitation on Corrosion, W.J. Tomlinson. The Effects ... 

Cycloproparenes do not form metal complexes with all transition metals. Reaction of cyclopropabenzene with diiron-nonacarbonyl yields polymer, while reaction with cyclopropanaphthalene leads to a stable product formed by metal and carbonyl insertion. Attempts to form cycloproparene-chromium complexes have also failed. ... 

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