Olefinic adds ketones

Free-radical autoxidation of aldehydes with 02 is facile and affords the corresponding peradds, which are used as oxidants for carbonyl compounds. The peracid can transfer an oxygen atom to a substrate such as an olefin or ketone, resulting in the formation of one equivalent of epoxide or ester and add as a co-produd in the absence of metal catalysts [59]. Kaneda and coworkers have developed several HT materials that are active for heterogeneous Baeyer-Villiger reactions with 02/aldehyde [60]. Combination with Lewis addic metals improved the reaction by allowing coordination of the peracid and the intermediate. 

Mercaptans add to olefins according to Markownikoff s rule in the presence of sulfur or sulfuric acid. The mode of addition is reversed by peroxides. The yields of sulfides are generally in the range of 60-90%. Somewhat lower yields (50-60%) are obtained by the addition of mercaptans to vinyl chloride and allyl alcohol. Conjugated olefinic aldehydes, ketones, esters, and cyanides add mercaptans and thiophenols in excellent yield. In certain cases the unsaturated compound may be converted directly to a symmetrical sulfide by addition of hydrogen sulfide (cf. method 388). 

Fiseber-Tropsch Iron + promoters 10-30 220-300 Olefins 90% paraflins, alcohols, adds, ketones, and aldehydes 10%... 

Substituted azirines add photocliemically to olefins and ketones to yield five-membered rings of the t5q e of pyrroline ((X=CRiR2) or S.oxazoline (X=0) 200,203), yjie primary nTi excitation, like the nre excitation of ketones, leads to the cleavage of a C—C single bond to the site of... 

Wittig olefination of ketone 49 with cyclopropylidenephosphorane afforded methylenecyclopropane 50. Subsequent cyclopropanation with dibromocarbene followed by debromination with zinc gave spiropentane 51. When 51 was treated with a rhodium catalyst under an atmospheric pressure of carbon monoxide, carbonylative skeletal rearrangement took place to give rise to the cyclopen-tenone 56. Mechanistically, the C4-C5 bond of spiropentane 51 adds oxidatively... 

Simple olefins do not usually add well to ketenes except to ketoketenes and halogenated ketenes. Mild Lewis acids as well as bases often increase the rate of the cyclo addition. The cycloaddition of ketenes to acetylenes yields cyclobutenones. The cycloaddition of ketenes to aldehydes and ketones yields oxetanones. The reaction can also be base-cataly2ed if the reactant contains electron-poor carbonyl bonds. Optically active bases lead to chiral lactones (41—43). The dimerization of the ketene itself is the main competing reaction. This process precludes the parent compound ketene from many [2 + 2] cyclo additions. Intramolecular cycloaddition reactions of ketenes are known and have been reviewed (7). 

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). 

Epoxidation of aldehydes and ketones is the most profound utility of the Corey-Chaykovsky reaction. As noted in section 1.1.1, for an a,P-unsaturated carbonyl compound, 1 adds preferentially to the olefin to provide the cyclopropane derivative. On the other hand, the more reactive 2 generally undergoes the methylene transfer to the carbonyl, giving rise to the corresponding epoxide. For instance, treatment of P-ionone (26) with 2, derived from trimethylsulfonium chloride and NaOH in the presence of a phase-transfer catalyst Et4BnNCl, gave rise to vinyl epoxide 27 exclusively. ... 

The add-catalyzed cyclodehydration of (Z)- and ( )-6-hydroxy-a,p-unsaturared ketones offers a mild synthesis of substituted furans. In the case of ( )-olefins, photochemical isomerisation was found to accelerate the reaction <96TL6065>. Reaction of alkynyl(phenyl)iodonium tetrafluoroborates with tropolone in the presence of a base yields 2-substituted furotropones (Scheme 16, <96TL5539>). 

Trimethylsilylmethyl Grignard or lithium reagents 1606 add to ketones such as cyclohexanone to give, via the intermediates 1607, the olefins 1608, often in high yields (Scheme 10.5). 

The addition products of MesSiCN 18 to carbonyl groups eliminate trimethylsilanol 4, in the presence of phosphoryl chloride in pyridine or of AICI3 in benzene, to give unsaturated nitriles. Thus ketone 1635 adds 18 and is subsequently converted, in a one-pot procedure, in 82% overall yield, into the olefin 1636 [27], whereas the adduct 1637 gives a mixture of the unsaturated nitriles 1638 [28] and ketone 1639 adds MesSiCN 18 and eliminates MesSiOH 4 or HMDSO 7, in one step, to give the a,y9-unsaturated nitrile 1640 [29] (Scheme 10.12). 

It appears that the ketone enolates add to the vinyl sulfone, followed by a condensation that leads to the thiane sulfone. The latter may be desulfonylated to provide olefins Similarly, enamino vinyl sulfones (345) can undergo a thermally allowed electrocyclic reaction between the termini of the enaminic double bond and the allyl sulfonyl portion in the intermediate anion (346) to afford a, ) -unsaturated thiene dioxides (348) as shown in equation 126 ... 

Ketones add to olefins to produce 2-alkyl derivatives upon photolysis<104-108) ... 

The quantum yields for oxetane formation have not been determined in every case, and only a few relative rate constants are known. The reactivities of singlet and triplet states of alkyl ketones are very nearly equal in attack on electron rich olefins. 72> However, acetone singlets are about an order of magnitude more reactive in nucleophilic attack on electron-deficient olefins. 61 > Oxetane formation is competitive with a-cleavage, hydrogen abstraction and energy-transfer reactions 60 64> so the absolute rates must be reasonably high. Aryl aldehydes and ketones add to olefins with lower quantum yields, 66> and 3n-n states are particularly unreactive. 76>... 

Japanese workers (50,51) were the first to observe optical activity in the addition of thiols to electron-poor olefins (eq. [9]) The e.e. was not determined, but these observations led us to attempt using a cinchona alkaloid as the catalyst in the addition of thiophenol to cyclohexenone. The reaction lends itself admirably to a scope, limitations, and mechanism study, and the results have been published in detail (19). An important mechanistic difference between the addition of the dodecanethiol to isopropenyl methyl ketone and the addition of thiophenol to a cyclohexenone (eq. [1]) lies in the sequence of chirality-producing steps. In the former case, chirality is produced when the proton adds to the a-caibon atom of the ketone—after thiol addition has taken place. In the latter... 

In the previous communication(7a) we postulated the initiation mechanism involving the attack of BuLi on the vinyl double bond of the butyl lsopropenyl ketone formed. However, from the results mentioned above we will propose the following mechanism for the polymerization of MMA with BuLi in toluene, which is slightly different from the previous one. On mixing the monomer with BuLi the initiator reacts with both olefinic and carbonyl double bonds of the monomer. The attack on the olefinic double bond produces the MMA anions, which add the monomer to form the growing chains(E). 

I. The dilithio derivative of N-methanesulfinyl-p-toluidine588 (42) adds to aldehydes and ketones to give, after hydrolysis, the hydroxysulfinamides 43, which, upon heating, undergo stereospecifically syn eliminations to give olefins.589 The reaction is thus a method for achieving the conversion RR CO - RR C=CH2 and represents an alternative to the Wittig reaction.590... 

Ordinary aldehydes and ketones can add to olefins, under the influence of uv light, to give oxetanes. This reaction, called the Patemo-Btichi reaction,781 is similar to the photochemical dimerization of olefins discussed at 5-49. In general, the mechanism consists of the... 

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