Methane carbonyl compounds

Dipyridiue-chromium(VI) oxide2 was introduced as an oxidant for the conversion of acid-sensitive alcohols to carbonyl compounds by Poos, Arth, Beyler, and Sarett.3 The complex, dispersed in pyridine, smoothly converts secondary alcohols to ketones, but oxidations of primary alcohols to aldehydes are capricious.4 In 1968, Collins, Hess, and Frank found that anhydrous dipyridine-chromium(VI) oxide is moderately soluble in chlorinated hydrocarbons and chose dichloro-methane as the solvent.5 By this modification, primary and secondary alcohols were oxidized to aldehydes and ketones in yields of 87-98%. Subsequently Dauben, Lorber, and Fullerton showed that dichloro-methane solutions of the complex are also useful for accomplishing allylic oxidations.6... 

Beller and coworkers reported hydrosilylation reactions of organic carbonyl compounds such as ketones and aldehydes catalyzed by Fe(OAc)2 with phosphorus ligands (Scheme 21). In case of aldehydes as starting materials, the Fe(OAc)2/PCy3 with polymethylhydrosiloxane (PMHS) as an H-Si compound produced the corresponding primary alcohols in good to excellent yields under mild conditions [67]. Use of other phosphorus ligands, for instance, PPhs, bis(diphenylphosphino) methane (dppm), and bis(diphenylphosphino)ethane (dppe) decreased the catalytic activity. It should be noted that frans-cinnamaldehyde was converted into the desired alcohol exclusively and 1,4-reduction products were not observed. 

Diazonium salts react with bis(methylsulfonyl) methane (107) (X = S02CH3) to yield a 1,3-diaryl tetrazolinone (111). The reaction proceeds through an azo (108) and a tetrazene (109) intermediate, followed by hydrolysis under the alkaline conditions of the reaction to the carbonyl compound (110). An unexplained oxidation leads to the 1,3-diaryl tetrazolinone (111) either directly or through the intermediate 110a (Scheme 15).18,35 A similar reaction occurs between a diazonium salt and the potassium salt of phenyl hydrazonomethane disulfonic acid (Scheme 15).175... 

Chan and Li reported that conjugated 1,3-butadienes were produced in moderate yields when carbonyl compounds reacted with 1,3-dichloropropene and zinc in water (Eq. 8.29).61 The use of 3-iodo-1-chloropropene instead of 1,3-dichloropropene greatly improved the yields. When the reactions were interrupted after their initial allyla-tions, subsequent base treatment of the intermediate compounds produced vinyloxiranes in high yields. Similarly, reactions of carbonyl compounds with 3-iodo-2-chloromethyl-l-propene followed by base treatment produced 2-methylenetetrahydrofurans (Eq. 8.30).62 Thus, the 3-iodo-2-chloromethyl-l-propene served as a novel trimethylene-methane equivalent.63... 

Trimethylsilyl triflate (McsSiOTf) acts as an even stronger Lewis acid than Sc(OTf)3 in the photoinduced electron-transfer reactions of AcrCO in dichloro-methane. In general, such enhancement of the redox reactivity of the Lewis acid complexes leads to the efficient C—C bond formation between organosilanes and aromatic carbonyl compounds via the Lewis-acid-catalyzed photoinduced electron transfer. Formation of the radical ion pair in photoinduced electron transfer from PhCHiSiMes to the (l-NA) -Mg(C104)2 complex (Scheme 11) and the AcrCO -Sc(OTf)3 complex (Scheme 12) was confirmed by the laser flash experiments [113]. 

The role of titanium salt is to activate the carbonyl compounds as Lewis acid. As described above, bis(iodozincio)methane (3) is nucleophilic enough to attack the carbonyl group of aldehydes or ce-alkoxyketones. In the reaction with simple ketones or esters, however, the addition of titanium salt is necessary to facilitate the nucleophilic attack. Instead of this Lewis acid activator, simple heating may induce the nucleophilic attack. Treatment of 2-dodecanone with 3 without titanium salt at higher temperature, however, does not improve the yield of alkene (Scheme 13). The reason for the low reactivity of 3 at higher temperature comes from the structural change of 3 into the polymeric methylene zinc 4 through the Schlenk equilibrium shown in equation 740. 

The conjugate addition of bis(iodozincio)methane to -unsaturated carbonyl compound gives y-zincio substituted enolate. As shown in equation 31, bis(iodozincio)methane reacts with. v-cis a,/3-unsaturated ketone in the presence of chlorotrimethylsilane to afford the silyl enol ether carrying a C—Zn bond. These zinc-substituted silyl enolates can be used for further coupling reactions (equation 32)54. 

Mechanism. Of great importance in permitting chemist lo explain rationally the reactivity of carbonyl compounds towattl di m -methane was the elucidation of its electronic structure. It is now accepted that a diazoalkane can be represented by a set of canonical structure ( A M C ), none of which Is an adequate representation by Itself Evidence for the linear nature of diaxoalkanee has been obtained hy various types of physical measurements, including electron diffraction and infrared fipectroeoopy.u,> 1WZ... 

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

Figure 17-3 Apparatus for the preparation of monohydroxymethylene aldol-addition products from methanal and carbonyl compounds with more than one a hydrogen...

Many phenols undergo aldol-like addition reactions with carbonyl compounds in the presence of acids or bases. Thus benzenol reacts with methanal under mild alkaline conditions to form (4-hydroxyphenyl)methanol ... 

J. Houben obtained methane, etc., by the action of magnesium alkyl haloids on the hydrazines the action of zinc ethyl and magnesium alkyl haloids on hydrazine has been studied by R. L. Krause the action of mono- and di- chloroacetic acids, by Jit. Busch and E. Meussdorffer ethyl chloroacetate, by A. Reissert and W. Kayser, and M. Busch and eo-workers phenylglyoxalic acid, by A. Elbers dinitrophenylhydrazine, by T. Curtius and M. Mayer ethyl dinitrobenzoate, by T. Curtius and A. Riedel dinitrobenzoic add, by T. Curtius and H. E. Bollenbach nitro- and amido-phthalhydrazides, by T. Curtius and A. Hoesch formaldehyde, by E. Riegler, and E. Rimini carbonyl compounds, by... 

This reaction has been made with various carbonyl compounds, e.g., cyclopentanone,27 cyclohexanone,20 cycloheptanone,27 cycloocta-none,27 1-tetralone,21 2-tetralone,28 variously substituted acetophenones,29 phenyl benzyl ketone,29 dibenzyl ketone,29 dibenzoyl-methane,18, 30 ethyl benzoylacetate,18 ethyl malonate,30 malon-anilide,30 and 2-(bisalkylthio)methylenecyclopentanones and cyclohexanones.27... 

The next three chapters by Fleming, Armesto, and Rao deal with different aspects of alkene photochemistry alkene [2+2]-photocycloaddi-tions to other alkenes, di-7i-methane (DPM) rearrangements of 1,4-dienes and oxa-di-7i-methane (ODPM) rearrangements of 3,y-unsaturated carbonyl compounds. Photocycloaddition of an ether-tethered 1,6-diene by Cu(I)-catalysis leads to the exo-selective formation of the bicyclic tetrahydrofuran derivative 4 [4]. By direct electronic excitation of a... 

Although only a few hydrocarbons have been studied it appears that most of them react with OH with a rate constant of ca. 109 M-1 s 1. Methane is about 4 times less reactive than this value, and cyclopentane and cyclohexane about 5 times more reactive. Alcohols, amines, ethers, and many esters also fall in the same range. Carboxylic acids and carbonyl compounds seems to be to a certain degree less reactive. Lower reactivity is also found for the protonated forms of amines and amino acids. Direct reaction of OH with the substituent is usually unimportant except for a few cases such as thiols, where H is easily abstracted from the SH, or nitroso com-... 

Lithiomethylphenyl tellurium, which is best prepared from bis[phcnyltelluro]methane and a lithioalkane, reacts with carbonyl compounds and alkyl halides. The greenish-yellow solution of lithiomethyl phenyl tellurium in THF is stable for at least 24 h when kept at 0° under an inert atmosphere2. 

Acyclic 295 and cyclic 296 hemithioacetals have been shown as precursors of formyl-lithium intermediates13. For the preparation of the starting methoxy(phenylsulfanyl) methane 295466 two main procedures can be used (a) nucleophilic substitution of chloro-methyl methyl ether with thiophenol under basic conditions467,468 and (b) boron trifluoride etherate-catalyzed condensation of thiophenol and dimethoxymethane166. 1,3-Oxathiane and its derivatives can be prepared by acetalization of the corresponding carbonyl compound with 3-mercaptopropanol. 

Dimethyl Either Carbonyl Compounds Higher Alcohols Methane... 

The Claiscn rearrangement of allyl vinyl ethers is usually an irreversible reaction due to the energetic benefit of forming aC-O double bond. However, in strained bicyclic systems the retro-Claisen rearrangement (3-oxa-Cope rearrangement) of y,<5-unsaturated aldehydes has been observed32. Sometimes equilibrium mixtures of vinyl ether and carbonyl compound were found. For example, the ratio of the valence tautomers, bicyclo[3.1.0]hex-2-ene-6-cWo-methanal to 2-oxabicyclo[3.2.l]octa-3,6-diene, is approximately 7 333. Nevertheless this reaction was used in the preparation of a key intermediate in a prostacyclin synthesis34. 

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