Olefinic adds aldehydes

This reduction is very likely the last step in the industrially important hydroformylation or oxo reaction for converting olefins into aldehydes (4). The catalytic species seems to be cobalt hydrocarbonyl, which first adds to the olefin as in Eq. (2). The alkylcobalt tetracarbonyl so formed then probably isomerizes to the acylcobalt tricarbonyl [Eq. (25)] and is reduced by hydrogen as in Eqs. (45) and (46). 

Aube and Golden (dJ) have demonstrated the utility of a combined intramolecular Diels-Alder/intramolecular Schmidt reaction to construct the azepinoindole intermediate 110 (Scheme 5). The Lewis add-catalyzed tandem intramolecular Diels-Alder/Schmidt reaction required azidodiene 109, which was prepared after five steps as a 85 15 mixture of diastereoisomers from diene 108 via a modified Julia olefination between aldehyde... 

Another very important reaction initially involving nucleophilic attack on an aldehyde carbonyl is the Wittig reaction. An yUd adds to the carbonyl forming a betaine intermediate which then decomposes to produce an olefin and a tertiary phosphine oxide. 

Oxo Synthesis. Ad of the synthesis gas reactions discussed to this point are heterogeneous catalytic reactions. The oxo process (qv) is an example of an industriady important class of reactions cataly2ed by homogeneous metal complexes. In the oxo reaction, carbon monoxide and hydrogen add to an olefin to produce an aldehyde with one more carbon atom than the original olefin, eg, for propjiene ... 

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). 

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. ... 

Methyl-2-furaldehyde gave a similar overall behaviour, but a penultimate effect was observed in its copolymerization with isopropenylbenzene whereby two molecules of the aldehyde could add together if the penultimate unit in the growing chain was from the olefin. This was borne out by the copolymers composition and spectra. The values of the reactivity ratios showed this interesting behaviour rx = 1.0 0.1, r2 = 0.0 0.1. An apparent paradox occurred the aldehyde, which could not homo-polymerize, had equal probability of homo- and copolymerization and the olefin, which homopolymerized readily, could only alternate. The structure arising from this situation was close to a regular sequence of the type ... 

Treatment of aromatic aldehydes such as p-anisaldehyde with Zn-powder and l,2-bis(chlorodimethylsilyl)ethane 45 give Zn-carbene adducts such as 2096 which add readily to olefins such as cyclohexene [22, 26] or styrene [26] to give high yields of cyclopropanes such as 2097 and the oxide 47 [26]. Acetals such as 2098 react analogously with cyclohexene to afford the endo and exo cyclopropanes 2099 and 2100 [22, 27] (Scheme 13.11). 

Thus, [HRh(C0)(TPPTS)3]/H20/silica (TPPTS = sodium salt of tri(m-sulfophenyl)phopshine) catalyzes the hydroformylation of heavy and functionalized olefins,118-122 the selective hydrogenation of a,/3-unsaturated aldehydes,84 and the asymmetric hydrogenation of 2-(6 -methoxy-2 -naphthyl)acrylic add (a precursor of naproxen).123,124 More recently, this methodology was tested for the palladium-catalyzed Trost Tsuji (allylic substitution) and Heck (olefin arylation) reactions.125-127... 

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>... 

A stereoselective route to 2-(phenylthio)-l,3-butadienes such as 327 or 328 was developed by Pearson et al. [167] with allylboranes as crucial intermediates. Addition of 9-BBN to allenyl sulfide 324 gives the allylborane intermediate 325, which subsequently adds to aldehydes (Scheme 8.89). Typical of Peterson olefinations, this reaction can also be terminated by two different work-up procedures, either acidic conditions leading to anti-elimination, which affords Z-configuration of dienes 327, or basic work-up resulting in a syn-elimination to form (E)-dienes 328. 

Raffinate-II typically consists of40 % 1-butene, 40 % 2-butene and 20 % butane isomers. [RhH(CO)(TPPTS)3] does not catalyze the hydroformylation of internal olefins, neither their isomerization to terminal alkenes. It follows, that in addition to the 20 % butane in the feed, the 2-butene content will not react either. Following separation of the aqueous catalyts phase and the organic phase of aldehydes, the latter is freed from dissolved 2-butene and butane with a counter flow of synthesis gas. The crude aldehyde mixture is fractionated to yield n-valeraldehyde (95 %) and isovaleraldehyde (5 %) which are then oxidized to valeric add. Esters of n-valeric acid are used as lubricants. Unreacted butenes (mostly 2-butene) are hydroformylated and hydrogenated in a high pressure cobalt-catalyzed process to a mixture of isomeric amyl alcohols, while the remaining unreactive components (mostly butane) are used for power generation. Production of valeraldehydes was 12.000 t in 1995 [8] and was expected to increase later. 

The group of Samuel Danishefsky at the Sloan-Kettering Institute for Cancer Research in New York has also been active in the synthesis of the natural epothilones and biologically active analogs. One of these syntheses also uses the olefin metathesis reaction (not shown). The synthesis in Scheme 13.51 uses an alternative approach to create the macrocycle. One of the key steps is a Suzuki coupling carried out at step H-(l,2) between a vinylborane and vinyl iodide. The macrocyclization is an aldol addition reaction at step H-4. The enolate of the acetate adds to the aldehyde, creating the C(2)-C(3) bond of the macrolactone and also establishing the stereocenter at C-3. 

The thus-formed peroxide then adds to the end of the eneone. Ozonization of the terminal olefin then leads to the aldehyde (63-5). The newly formed carbonyl group is then reacted with the ylide from phosphonium salt (63-6) under salt-free conditions. This results in the addition of the f7W-trifluoromethylbenzyl moiety with cis geometry about the double bond. There is thus obtained arteflene (63-7) [72]. 

It also catalyzes a variety of reactions of hydrogen with olefins, aldehydes, and carbinols. The best known of these is the hydroformylation (Oxo) reaction, discovered by Roelen (40), in which a molecule of hydrogen and a molecule of carbon monoxide add simultaneously to an olefin (usually at temperatures of 75° to 200° and partial pressures of 50 to 150 atm. each of CO and H2) to form an aldehyde ... 

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... 

Small alkylperoxy and alkoxy radicals can decompose uni-molecularly, though their rate constants are often in the second-order region. They abstract hydrogen atoms from alkanes, aldehydes, esters, and acids, add to olefins, and may react with 02. Furthermore, interactions with other radicals can lead to disproportionation or combination. These reactions are reviewed, and particular attention is given to CH 02 and CH30 a number of rate constants are estimated. 

Huisgen has stated that the driving force behind the 1,3-dipolar addition is stronger the more the loss of T-bond energy in the reactants is overcompensated by the energy of the two new bond energy is O-N < N-N < C-N, azides do not add at all to aldehydes and ketones and add with more difficulty to nitriles than to olefins. Phenyl azide, for instance, adds preferentially to the C-C double bond of acrylonitrile.194 103 This is also the reason why the condensation products of aldehydes and primary amines, which essentially exist in the Schiff-base structure 46a, react in the tautomeric enamine form 46b.2 ... 

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