Formaldehyde with organometallic

Reaction between organometallic 6-46 Condensation of formaldehyde with... 

Monomers of formaldehyde vapor that can be dissolved in an inert hydrocarbon such as heptane along with an initiator. Initiators include Lewis acids such as BFj (Table 17,2, LA) as well as amines, phosphines, arsines, stibenes, organometallic componnds, and transition metal carbonyls. The polymer is often referred to as acetal homopolymer, polyacetal, or poly(oxymethylene). All of these terms distinguish the useful, stable polymer from polyformaldehyde, the thermally unstable, waxy material that forms easily from the pure monomer. Because of the instability of the chain structure and its tendency to unzip, esterification of the end-group hydroxyls or end blocking with acetic acid is one answer (Table 17.2, LA). Another is the copolymerization of formaldehyde with monomers that will interrupt the chain sequence. Ethylene oxide is one such monomer. 

The presence of unsaturation in the side chain is also compatible with antihistaminic activity. Mannich condensation of p-chloroacetophenone with formaldehyde and pyrollidine affords the amino ketone, 109. Reaction with an organometallic reagent from 2-bromopyridine gives 110. Dehydration leads to triproli-dine (111). ... 

Reaction of organometallic compounds with carbonyl compounds a. primary alcohols from methanal (formaldehyde)... 

The synthetic method (b) combines the formation of a primary or secondary alkynol [from formaldehyde or an aldehyde respectively and an organometallic acetylenic reagent (Section 5.4.2, p. 532)] with the semihydrogenation of the triple bond to a double bond. As noted in Section 5.2.2, p. 493, appropriate selection of catalyst is necessary in the hydrogenation step to ensure the formation of either the ( )- or the (Z)-isomer. The specific formation of the allylic alcohol, CH2=CH-CH(OH),R, is from a vinylmagnesium halide (Expt 6.41) and an aldehyde. 

The reaction of an organometallic reagent with formaldehyde produces a primary alcohol ... 

Monoalkylation of primary amines. A two-step sequence for this reaction involves conversion of the amine to the N-(cyanomethyl)amine (2) by reaction with chloroaceto-nitrile or with formaldehyde and KCN. Reaction of 2 with an organolithium or a Grignard reagent generates an unstable formaldehyde imint (a) that reacts with a second equivalent of the organometallic reagent to form a secondary amine (3). 

For example, unbranched aliphatic acids with an even number of carbon atoms will be generously represented, while one finds a nearly complete absence of odd-numbered and branched acids. Nature produces an incredible diversity of the most ingeniously constructed cyclic products containing cycloaliphatic, aromatic, or heterocyclic moieties, but such derivatives like aniline or thiophe-nol, as well as plethora of other simple representatives of these classes, are not in the list of naturally occurring substances. Such important types as alkyl halides, nitro compounds, and diazo compounds would be sparsely represented by very rare (if any) examples. Even the simplest compounds like formaldehyde, chloroform, diethyl ether, dioxane, etc., which are trivial to organic chemists, turn to be rather exotic for Nature. In the list of items provided by Nature one will notice the almost complete absence of various organometallic compounds, as well as many other classes of structures of immense scientific and practical significance. 

Bernard, K. A., Atwood, J. D. Evidence for carbon-oxygen bond formation, aldehyde decarbonylation, and dimerization by reaction of formaldehyde and acetaldehyde with trans-ROIr(CO)(PPh3)2. Organometallics 1988, 7, 235-236. 

An environmental application of liquid extraction is the removal of trace organics from water. Examples are the separation of acetic acid-water mixtures and removal of solvents, insecticides, pesticides, etc., from water. It can also be applied to the separation of liquids with close boiling points or those that form azeotropes, such that distillation is not useful. In addition, zero- or low-volatility compounds, such as metals and organometallic derivatives, can be separated by liquid extraction as can mixtures of water-hydrogen bonded compounds, such as formaldehyde. Solid extraction (leaching) can be used to remove organics or heavy metals from contaminated soils, sludges or contaminated equipment. 

Since carbon dioxide is a thermodynamically stable, highly oxidized compound, its synthetic utilization requires some kind of a reduction -reaction with molecular hydrogen is a distinct possibility. Stepwise reduction of C02 with H2 may yield formic acid, formaldehyde, methanol and finally methane, together with CO or Fischer-Tropsch-type derivatives as shown on Scheme 3.42. In aqueous organometallic catalysis the most common product of such a reduction is formic acid. Formation of carbon monoxide, formaldehyde, and methane has already been reported, however, methanol and Fischer-Tropsch type products were not observed. 

The reaction of allyl organometallics (8) with achiral aldimines (9) is the simplest combination of reactants, stereochemically, and affords (except in the case of formaldehyde imines) homoallylamines (10) containing one stereocenter (equation 2). These reactions, which typify the general scope of allyl organo-metallic-imine reactions are surveyed in Table 2. Reactions of allyl-borane, -titanium and -aluminum reagents are not shown in Table 2, only because they have been reported in reactions with chiral imines and are discussed in Sections 4.3.2.1.2 and 4.3.2.2. 

Messenger-RNA mRNA) for gene cloning, 242 Mesylates. See Methanesulfonic acid, esters Metal organyls. See Organometallic compounds MethanaL See Formaldehyde Methanamine, 1,1-dimethoxy-jV.Mdiinethyi- formylation with, 82... 

For the introduction of a hydroxymethyl group our procedure with dry polymeric formaldehyde (paraform) in many cases works satisfactorily [2], We have noticed that, irrespective of the nature of the organometallic species (mostly Li as counterion), the reaction in Et20 or THF does not start below 15 °C. This might be explained by assuming that at room temperature a sufficiently high rate of dissociation into the monomer is attained. Liquid ammonia is generally unsuitable as a solvent for the hydroxymethylation with paraformaldehyde. 

An organometallic route to muscarine derivatives has been developed (Scheme 1). Reduction of the aa -dibromo-ketone (1) with Fe2(CO)9 in the presence of DMF provided the furanone (2) in good yield. Acetylation of (2) afforded the corresponding enol acetate, which upon Mannich reaction with dimethylamine and formaldehyde gave the furan derivative (3). Deacetylation followed by dissolving-metal reduction and quaternization with methyl iodide gave two isomeric 4-methyl-muscarine salts (4). These compounds showed physiological properties characteristic of the muscarine alkaloids. 

The conversion of organometallic complex ( j -formaldehyde complex Cp 2Nb(Cl)( j -CH2O)) to the diamagnetic hydride complex (Cp 2Nb(H)( j -CH20)) is an organometallic version of the Bouveault-Blanc reduction. This reaction provides access to reduction products that are not available with the use of hydridic reductants and requires the presence of alcohol to facilitate the second reduction event. ... 

---