Alkali metal carbonyls

LiAlH4 as this avoids protonation of the enolate and the production of any over-reduction products. Cholest-4-en-3-one may be reduced to cholestanone (5a 5/8,1 19) with alkali-metal carbonyl chromates. The studies on intramolecular hydride shifts on hydroxy-ketones and -aldehydes have been extended. " The hydride shifts were examined in a number of y- and 5-hydroxy-carbonyI compounds by heating the substrates with alkaline alumina containing D2O. Exchange of protons on the carbon a to both oxygen functions signals the intramolecular hydride shift typically, the hemiacetals (95) and (96) each incorporate up to six deuterium atoms. The general conclusion, in common with literature precedent, is that, whereas 1,5-shifts are common, 1,4-shifts are rare. 

Carbon monoxide is very toxic, rapidly giving a bright red complex with the hemoglobin of blood. Carbon monoxide reacts with alkali metals in liquid ammonia to give the alkali metal carbonyls these white solids contain the [OCCO]2 ion. 

A more recent search of the CSD for alkali metal/carbonyl crystal structures also confirmed these re-sults. The average Li—O bond length and the Li—O—C bond angle were found to be 1.99 0.07 A... 

Infrared spectroscopy in the CO stretching region provides a sensitive probe for detecting contact ion pair formation between cations and carbonylates (12,13). Good examples are provided by the early work on the interaction of cations with tetracarbonylcobaltate (12) and by more recent work on a variety of metal carbonyl anions (13,14). In solvents such as THF, alkali metal carbonylates appear to be present in two or three different forms tight (contact) ion pairs, looser ion pairs, and ion triplets. For example, Fig. 5 shows the IR spectrum of Na[Mn(CO)s] in THF and its deconvolution into two different sets of bands, which are associated with two different species in solution (14). For one of these the evidence points to a contact ion pair of structure 6. 

Sometimes mercury derivatives formed in the preparation of alkali metal carbonyls by reduction with sodium amalgam are potential contaminants in metal carbonyl derivatives prepared from the resulting sodium compounds. Moreover, in large-scale preparations the quantity of mercury required for the dilute amalgams can be very large and thus inconvenient. It is possible to avoid the presence of mercury in reductions of metal carbonyls such as Mn2(CO)io and Co2(CO)g by the use of lithium wire in tetrahydrofuran 38). 

Cobalt has an odd number of electrons, and does not form a simple carbonyl in oxidation state 0. However, carbonyls of formulae Co2(CO)g, Co4(CO)i2 and CoJCO),6 are known reduction of these by an alkali metal dissolved in liquid ammonia (p. 126) gives the ion [Co(CO)4] ". Both Co2(CO)g and [Co(CO)4]" are important as catalysts for organic syntheses. In the so-called oxo reaction, where an alkene reacts with carbon monoxide and hydrogen, under pressure, to give an aldehyde, dicobalt octacarbonyl is used as catalyst ... 

Reduction with metal deuteride complexes (section Ill-A) is undoubtedly the most convenient way to convert carbonyl compounds into the corresponding deuterated alcohols. For stereochemical reasons, however, it is sometimes necessary to resort to reductions with alkali metals in O-deuterated alcohols, or in liquid deuterioammonia-O-deuterioalcohol mixtures. 

Hypochlorites- are obtained by reaction of fluorinated carbonyl compounds, such as carbonyl lluonde, with an alkali metal fluoride and chlorine fluoride f62, 720]... 

Ni(CO)4] is readily oxidized by air and can be reduced by alkali metals in liquid ammonia or thf to yield a series of polynuclear carbonylate anion... 

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.). 

In addition reactions to chiral carbonyl compounds, the stereochemical course taken by resonance-stabilized alkali metals or magnesium benzyl anions resembles that taken by localized carbanions of similar bulk. Thus, conditions can be delineated which lead to either the steric approach or chelation control the following serve as examples. 

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

Simple allyl alkali metal compounds have only a small capability for discriminating between diastereotopic faces of carbonyl compounds. Although a matter of simple diastereoselectivity, this can be concluded from the reaction of conformationally locked 4-/erf-butylcyclohexanone... 

Generally, in the nucleophilic addition to carbonyl groups, either magnesium compounds or alkali metal compounds (such as the Li, Na and K derivatives) are used. In some cases even potassium carbonate or piperidine were used as the base for condensation with sulfones. Good results were obtained when concentrated aqueous NaOH was used under phase-transfer conditions288,297,333. 

When a carbonyl group is bonded to a substituent group that can potentially depart as a Lewis base, addition of a nucleophile to the carbonyl carbon leads to elimination and the regeneration of a carbon-oxygen double bond. Esters undergo hydrolysis with alkali hydroxides to form alkali metal salts of carboxylic acids and alcohols. Amides undergo hydrolysis with mineral acids to form carboxylic acids and amine salts. Carbamates undergo alkaline hydrolysis to form amines, carbon dioxide, and alcohols. 

Alkali Metal Derivatives of Metal Carbonyls, 2, 1S7 Alkyl and Aryl Derivatives of Transition Metals, 7, 1S7 Alkyl cobalt and Acylcobalt Tetracarbonyls, 4, 243 Allyl Metal Complexes, 2, 32S... 

In these cases, one is limited to the growth of single crystals of the transition metals since it is those metals which form volatile carbonyl compounds. The alkali metals, alkaline earth metals and certain of those elements which are allotropic in nature are not at aH suited for this type of crystal growth. 

Interaction of the CO molecule with CuX-FER zeolites (X is an alkali-metal or proton as a co-cation) was investigated by IR spectroscopy and DFT calculations. An absorption band at 2138 cm 1 observed in IR spectra of CO on CuK- and CuCs-FER zeolites was assigned to a new type of CO adsorption complex on heterogeneous dual cation sites. CO molecule interacts simultaneously with Cu+ and alkali metal cations (via C- and O-end, respectively) in this type of complex. Interaction of CO with the secondary (alkali metal) cation led to a slight destabilization of the carbonyl complex. 

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