Hydroformylation functionalized olefins

Functional Olefin Hydroformylation. There has been widespread academic (18,19) and industrial (20) interest in functional olefin hydroformylation as a route to polyfiinctional molecules, eg, diols. There are two commercially practiced oxo processes employing functionalized olefin feedstocks. Akyl alcohol hydroformylation is carried out by Arco under Hcense from Kuraray (20,21). 1,4-Butanediol [110-63 ] is produced by successive hydroformylation of aHyl alcohol [107-18-6] aqueous extraction of the intermediate 2-hydroxytetrahydrofuran, and subsequent hydrogenation. 

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 first highly enantioselective asymmetric hydroformylation was the asymmetric hydroformylation of styrene.120 In 1991, Stille et al.121 reported the achievement of up to 96% ee using a chiral bisphosphine complex of PtCl2 as the catalyst in combination with SnCl2. However, the Pt(II)-catalyzed hydroformylation of arylethenes and some functionalized olefins has several disadvantages, such as low reaction rates, a tendency for the substrates to undergo hydrogenation, and poor branched-to-linear ratio. 

Highly crosslinked polymer-supported-BINAPHOS ligands were effective for the hydroformylation of styrene and other functionalized olefins (ee s up to 89%). The catalyst could be recovered and reused at low stirring conditions [61,62]. 

To date, three methods have been described for the synthesis of aldehyde functional polysiloxanes (1) in patent literature, but these are not practiced. The hydroformylation of olefinic siloxanes with carbon monoxide and hydrogen under high pressure and temperature conditions is possible (Scheme 1, eq. (1)), but produces a mixture of... 

From 2,5-dihydrofuran, the most obvious derivative is tetrahydrofuran (THF), formed by the hydrogenation of the C=C bond. The C=C bond is also reactive for hydroformylation and olefin metathesis to add additonal functionality and structure. As stated earlier, the next intermediate, 2,3-dihydrofuran (2,3-DHF) serves as the gateway to CPCA family of chemicals. Hydration of 2,3-DHF produces 2-hydroxytetrahydrofuran, which can be readily converted to gamma-butyrolactone, pyrrolidinone (and N-substituted pyrrolidinones). Finally hydrogenation of hydroxytetrahydrofuran yields 1,4-butanediol in high yields. 

The examples above, demonstrate that a great variety of functionalized olefins can be hydroformylated with Rh, but each substrate must be approached individually when selecting a proper T, P and ligand. 

Various papers describe the aqueous biphasic hydroformylation for simple olefins as well as for functionalized olefins or dienes [154-174] (cf. the Section 6.1). In recent work [175], the synthesis of n-nonanal by consecutive isomerization and hydroformylation reactions of trans-4-octene has been described. The catalyst used was the in situ combination of Rh(acac)(CO)2 and the chelate phosphite BIPHE-PHOS. Performing the reaction in propylene carbonate the selectivity to n-nonanal could be raised up to 95%. If after the reaction the product is extracted with dodec-... 

These considerations now provide a guideline for the development of other potential catalysts for the use of CO + H2O in the hydroformylation of olefins. If the catalyst is to function in the same manner as just described for Fe(CO)s, then a minimum requirement is that the system form a metal carbonyl which will be readily attacked by a weak base to form an anion analogous to 1. A weak base is essential because CO2 is an inevitable by-product, and only the carbonate salts of weak bases regenerate the base and CO2 upon heating. Thus, if the system is to be catalytic in base as well, then clearly only a weak base can be used. This would appear to be the critical requirement, for the literature indicates that metallocarboxylic acids readily decarboxylate (12), and the final step in Reaction 6, the protonation of a hydridometalcarbonyl anion, would seem to offer no problem provided the catalyst system was not in a highly basic medium. 

Various unsaturated compounds can be inserted into the metal alkyl, aryl, and alkenyl complexes to give new organometallic complexes having various functional groups. The insertions of carbon monoxide (CO) and isocyanide (CNR) into transition metal-carbon a-bond are particularly important processes, since a carbon unit can be increased in the process and the acyl type complexes formed by the insertion processes can be subjected to further transformations to synthesize useful organic compounds. For example, the CO inserhon constitutes a fundamental step in industrially important processes such as hydroformylation of olefins, acetic acid synthesis from methanol and CO, Fischer-Tropsch process, amidocarbonylation, olefin and CO copolymerizahon processes as well as in a variety of laboratory syntheses of carbonyl containing compounds. 

Functionalized olefins can be classified in two groups the <5-fimctionalized olefins in which the functional group is not directly branched on the double bond but on an alkyl chain of the olefin as in the case of oct-7-en-l-al or linoleic alcohol, and the a-functionalized olefins in which the functional group is directly branched on the double bond as in the case of methyl acrylate or phenyl vinyl ether. The results described for these two groups will be discussed separately. Hydroformylation of water-soluble olefins in two-phase system with water-insoluble catalysts is far beyond the scope of this chapter and will not be discussed here (1, 2]. 

To our knowledge, the only industrial application of the water-soluble catalyst for the hydroformylation of ( functionalized olefins has been developed by Kuraray [11]. In this process, oct-7-en-Tal is hydroformylated into 1,9-nonanedial by using a rhodium catalyst and the monosulfonated triphenylphosphine (cf. also Section 2.4.4.2). 

The first work on a-functionalized olefins was focused on the hydroformylation of acrylic esters [Eq. (5)] [16-19]. 

Although the scope of the aqueous biphasic hydroformylation of functionalized olefins stiU needs to be deeply investigated, these few studies demonstrate clearly that fimctionalized olefins can be hydroformylated efficiently in an aqueous biphasic medium. However, it should be kept in mind that water is not only an inert mobile phase. Water can also act as a reactant or a coordinating solvent that modifies catalytic species. So, in some cases, imexpected increases or decreases in the activity or selectivity can be observed. 

Commercial applicahons have advanced to the pilot plant scale so far. It can be speculated that in the overall scheme the aforementioned issues of catalyst stability and membrane stability and performance are critical issues. In the particular case of rhodium-catalyzed hydroformylation (for higher aUcenes or functional olefins) for the synthesis of fine chemicals it can be assumed that, as a nonscientific and nontechnical driver, the price of rhodium will contribute to the commercial success. 

The advances in the hydroformylation of olefins carrying functional groups have been summarized in a review which stresses the potential of hydroformylation for the production of fine chemicals and high value-added products. The kinetics of the Reppe hydroformylation of ethylene catalyzed by [Fe(CO)s] at 110-140 °C in basic solution have been determined. Propionaldehyde and propanol... 

Silylformylation of olefins and alkynes can be regarded as the silicon version of hydroformylation. The reaction involves the concomitant introduction of a silyl group, derived from a hydrosilane, and a formyl group derived from insertion of carbon monoxide, thus producing functionalized olefins and dienes, which are useful synthons. ... 

Cyclohydrocarbonylation (CHC) is the hydroformylation of a functionalized olefin followed by concomitant intramolecular nucleophillic attack to the newly formed aldehyde moiety leading to a cyclized product. As a variant, the CHC reaction also includes an intramolecular cascade process involving the hydrocarbonylation of a functional alkene, generating an acyl-metal intermediate, which undergoes an intramolecular nucleophilic attack to give the corresponding cyclic compound. CHC reactions have been developed into sophisticated cascade reactions forming bicylic and polycyclic compounds. ... 

The concept of SI L catalyst has been developed quickly in the last decade. Holderich et al. [4] added acidic chloroaluminate ILs to various types of supports, and the catalytic activities of the immobilized ILs were found to be higher than those of the conventional catalysts under the same conditions. Inspired by this work, SIL catalysts have been widely used in the coupling reactions for olefin hydroformylation [5], olefin metathesis [6], Heck reactions [7], and hydroamination [8], and so on. SIL catalytic systems have also been reported for some other reactions, such as water-gas shift reaction [9], dihydroxylation of olefins [10], and hydrogenation [1 Ij. The solid supports used include magnetic NPs [12], mesoporous molecular sieves [13], soluble organic ions [14], noncovalently solid-phase [15], IL-functionalized carbon nanotubes [16], polymer cocktail [17], and so on. 

Moreover, and in contrast to products of vinyl compounds, the hydroformylation of p-functionalized olefins produces aldehydes, which may frequently react in additional steps under the participation of the first functional group. In this manner, ring closure can occur. 

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