Formaldehyde reactions with organometallic

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

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

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). 

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. 

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. 

Similarly, reactions of organometallic reagents (RLi or RMgX) with aldehydes other than formaldehyde give secondary alcohols. The R of the organometallic reagent can either be the same as that of the aldehyde or different (Fig. 16.62). 

The reaction of organometallic compounds with formaldehyde results in primary alcohols. In the electrostatic potential maps of the example below, the electron-rich (orange-red) carbon of the butylmagnesium bromide is seen to attack the electron-poor (blue) carbon of formaldehyde to give 1-pentanol. 

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

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. 

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. 

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. ... 

In the absence of organometallic cocatalyst, the hexavalent chromate species on the Phillips catalyst is first reduced to a lower valence state by ethylene monomers. Experimentally, we found that the exposure of ethylene to Phillips catalyst during the induction period at RT led to the reduction of Cr(VI)0 c surf precursors to Cr(II) 0 c surf species with the simultaneous formation of formaldehyde and unsaturated hydrocarbon species, such as propylene and butene. The proposed reaction mechanisms during the induction period are shown in Scheme 15 [79]. 

Prior to the development of methods for caiTving out the direct reaction of fomialdehyde vdth acetydene or monosubstituted acetylenes (page 237), the only satisfactory procedime for preparing acetylenic alcohols from formaldehyde involved the intennediate preparation of organometallic compounds. Substituted pi Opargyl alcohols are obtained in yields of 70 per cent or better by reaction of monosubstituted acetylenic Grignard compounds with gaseous formaldehyde ... 

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