Ketones from carbonylation

In organic chemistry, the C—C bond-forming feature of the condensation reactions is widely used for the synthesis of linear and mainly branched aldehydes or ketones from carbonyl compounds of shorter carbon chains. Aldehydes or ketones may be condensed to dimeric or heavier polymeric products. 

Apparently, 4.54 is extremely reluctant to undergo a retro Mannicli reaction. Riviere demonstrated that this behaviour is not unusual for (3-amino ketones. From the study of a large number of Mannich adducts. Riviere concludes that the retro Mannich reaction requires an aromatic group next to the carbonyl functionality. Qearly, 4.54 lacks this arrangement. 

Alcohols can be prepared from carbonyl compounds by reduction of aide hydes and ketones See Table 15 3... 

This pattern of increased reactivity resulting from carbonyl group prolonalion has been seen before m nucleophilic additions to aldehydes and ketones (Section 17 6) and... 

Many other organometaUic compounds also react with carbonyl groups. Lithium alkyls and aryls add to the ester carbonyl group to give either an alcohol or an olefin. Lithium dimethyl cuprate has been used to prepare ketones from esters (41). Tebbe s reagent, Cp2TiCH2AlCl(CH2)2, where Cp = clyclopentadienyl, and other metal carbene complexes can convert the C=0 of esters to C=CR2 (42,43). 

Ethylene oxide reacts with phosphonium haUdes to give yUdes, which are used to synthesize olefins from carbonyl compounds, such as aldehydes and ketones (92). 

A one-step synthesis o( mtnles from carbonyls by a reductive cyanation with tosylmethyl isocyanide (TosMIC), also synthesis of 1,3-azole or of ketones... 

In a chiral aldehyde or a chiral ketone, the carbonyl faces are diastereotopic. Thus, the addition of an enolate leads to the formation of at least one stereogenic center. An effective transfer of chirality from the stereogenic center to the diastereoface is highly desirable. In most cases of diastereoface selection of this type, the chiral aldehyde or ketone was used in the racemic form, especially in early investigations. However, from the point of view of an HPC synthesis, it is indispensable to use enantiomerically pure carbonyl compounds. Therefore, this section emphasizes those aldol reactions which are performed with enantiomerically pure aldehydes. 

Carboxylic acids, a-bromination of 55, 31 CARBOXYLIC ACID CHLORIDES, ketones from, 55, 122 CARBYLAMINE REACTION, 55, 96 Ceric ammonium nitrate [Ammonium hexa mtrocerate(IV)[, 55, 43 Chlorine, 55, 33, 35, 63 CHROMIUM TRIOXIDE-PYRIDINE COMPLEX, preparation in situ, 55, 84 Cinnamomtnle, a-phenyl- [2-Propeneni-tnle 2,3-diphenyl-], 55, 92 Copper(l) iodide, 55, 105, 123, 124 Copper thiophenoxide [Benzenethiol, copper(I) salt], 55, 123 CYCLIZATION, free radical, 55, 57 CYCLOBUTADIENE, 55, 43 Cyclobutadieneiron tricarbonyl [Iron, tn-carbonyl(r)4-l,3-cyclo-butadiene)-], 55,43... 

Ketones from Aoetylenes Alkylation of carbonyl compounds (p T 108) with propargyi halides gives 7,5-acetyienic ketones. Hydration then gives a 1,4-diketone of a type we shall use in Chapter T 25 as in the following example, ... 

In this chapter, the definitions used by Perrin in his book on pA a prediction (which also includes a very convenient compilation of o values) will be used. One must be alert to the importance of the number of hydrogens directly attached to the carbonyl carbon several groups have pointed out that aldehydes and ketones give separate but parallel lines, with formaldehyde displaced by the same amount again. What this means is that given one equilibrium constant for an aldehyde (or ketone) one may estimate the equilibrium constant for other aldehydes (or ketones) from this value and p for the addition using a value from experiment, if available, or estimated if necessary. This assumes that there is no large difference in steric effects between the reference compound and the unknown of interest. 

Oxidation of alcohol produces hydrogen peroxide and carbonyl compound simultaneously (aldehyde and ketone from primary and secondary alcohols, respectively). Carbonyl compound is formed as a result of alkylhydroxyperoxyl radical decomposition... 

The Meerwein-Ponndorf-Verley reaction is a classic method for ketone/ aldehyde carbonyl group reduction, which involves at least 1 equivalent of aluminum alkoxide as a promoter. In this reaction, the hydrogen is transferred from isopropanol to the ketone/aldehyde substrate, so the reaction can also be referred to as a transfer hydrogenation reaction. 

Mannich and related readions provide one of the most fundamental and useful methods for the synthesis of p-amino carbonyl compounds, which constitute various pharmaceuticals, natural products, and versatile synthetic intermediates.1271 Conventional protocols for three-component Mannich-type readions of aldehydes, amines, and ketones in organic solvents indude some severe side reactions and have some substrate limitations, espedally for enolizable aliphatic aldehydes. The dired synthesis of P-amino ketones from aldehydes, amines, and silyl enolates under mild conditions is desirable from a synthetic point of view. Our working hypothesis was that aldehydes could read with amines in a hydro-phobic reaction fidd created in water in the presence of a catalytic amount of a metal triflate and a surfactant to produce imines, which could then read with hydrophobic silyl enolates. 

Dialkylboron trifluoromethanesulfonates (Inflates) are particularly useful reagents for the preparation of boron enolates from carbonyl compounds, including ketones, thioesters and acyloxazoiidinones. Recentiy, the combination of dicylohexyiboron trifluoromethanesulfonate and triethyiamine was found to effect the enolization of carboxyiic esters. The boron-mediated asymmetric aldoi reaction of carboxyiic esters is particuiariy usefui for the construction of anti p-hydroxy-a-melhyl carbonyl units. The present procedure is a siight modification of that reported by Brown, et ai. ... 

Radical carbonylation reaction serves as a powerful tool for the synthesis of a range of carbonyl compounds. Radical carbonylation has been successfully applied to the synthesis of functionalized ketones from alkyl, aryl, and alkenyl halides.The radical aminocarbonylation reaction of alkynes and azaenynes provided efficient routes to 2-substituted acrylamides, lactams, and pyrrolidinones. For example, the aminocarbonylation of 4-pentyn-l-yl acetate 318 initiated by tributyltin hydride (Bu"3SnH) (30mol%) with AIBN (20mol%) gave acrylamide 325 in 92% yield (Scheme 43).A proposed mechanism starts from the addition of tributyltin radical 319 to alkyne... 

The formation of chiral alcohols from carbonyl compounds has been fairly widely studied by reactions of aldehydes or ketones with organometallic reagents in the presence of chiral ligands. Mukaiyama et al. 1081 obtained excellent results (up to 94% e.e.) in at least stoichiometric addition of the chiral auxiliary to the carbonyl substrate and the organometallic reagent. 

Functionalized zinc carbenoids have been prepared from carbonyl compounds by an indirect strategy. The deoxygenation of a carbonyl compound to an organozinc carbenoid can be induced by a reaction with zinc and TMSCl. Therefore, the aldehyde or ketone, when treated with TMSCl or l,2-bis(chlorodimethylsilyl)ethane in the presence of an alkene, generates the cyclopropanation product. This method is quite effective for the production of alkoxy-substituted cyclopropane derivatives. A 55% yield of the... 

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