Hydroformylation of functionalized olefins

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). 

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. 

Cyclohydrocarbonylation (CHC) is defined as process of hydroformylation of functionalized olefins followed by concomitant intramolecular nucleopbillic addition to tbe newly formed aldehyde moiety leading to a cyclized product (7). CHC reactions have been developed into sophisticated cascade reactions allowing for the formation of both bicyclic and polycyclic nitrogen and oxygen heterocycles (136). 

The aqueous biphasic processes require a minimum solubility of the reactants S in the catalyst phase [196, 205]. Therefore, hydroformylation of higher olefins (approx. > Cg) or functionally substituted olefins is more difficult but offers various advantages, such as the simplification of reaction sequences and reduced expenditure for the catalyst cycle. So far, work on these biphasic processes for the conversion of higher olefins, except for Kuraray s recent devel-... 

Using the hydroformylation of various olefins a variety of olefins was tested with the triisooctylamine-TPPTS salt [12, 13]. It could be shown that different olefmic compounds and structures (cycloaliphatic, internal, functionalized) can be used with the re-immobilized catalyst system (see Table 2). 

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. 

In aqueous two-phase hydroformylation of 1-octene and 1-dodecene the amphiphilic ligands of type 25 (n = 10, 12) have been shown to form Rh catalysts that are superior to Rh/TPPTS systems [129]. The bicyclic ligands 26 were considered to be of interest as substitutes for TPPMS in the new oxo process developed by Union Carbide for the hydroformylation of higher olefins using N-methylpyrroli-done or polyalkylene glycols as solvents [7, 51, 52], Rh(I) complexes [Rh(26)2]+ [96] showed, however, a very poor performance as catalysts in biphasic systems for hydrogenation and hydroformylations in contrast to non-functionalized 1-phospha-norbornadiene [98], This was explained by formation of P,P(0) chelates blocking... 

Metal ion cooperativity has been observed with the Rh-Zn complex 34 which catalyzes hydroformylation of functionalized terminal olefins with no induction period. It is possible than Zn(II) functions as an internal acceptor which removes the chloride ion from the Rh(I) center during formation of the active species. 

The regioselective hydroformylation of functionalized and nonfunctionalized olefins can also be performed by platinum compounds [26] in chlorostannate ionic liquids as solvents for homogeneous catalysis (entries 20-22, Table 6.1). Dissolved in chlorostannate ionic liquids, the Pt catalyst shows enhanced stability and selectivity in the hydroformylation of methyl-3-pentenoate compared to the identical reaction in conventional organic solvents. The moderate Lewis acidity of these ionic liquids allows the activation of the Pt catalyst combined with tolerance of the functional groups in the substrate. In the case of 1-octene hydroformylation, a biphasic reaction system could be performed using the chlorostannate ionic liquid. 

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... 

Figure 8.4. Chemoselectivity as a function of system pressure during the hydroformylation of long chain olefins with Rh/PEt3 catalysts. The change in chemoselectivity has been correlated with the transition from biphasic to monophasic reaction conditions...

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]. 

Hydroformylation is the process of coupling carbon monoxide to an olefin with a reductive catalyst and hydrogen to produce an aldehyde-functionalized substrate. This coupling is typically followed by hydrogenation to produce a primary hydroxyl group. Several academic and commercial programs have participated in the development of hydroformylated triglycerides and fatty acid derivatives for use in polyurethanes. Two main processes for the hydroformylation of seed oils have been utilized. 

With regard to the structure of the olefins, tetrasubstituted olefins do not undergo hydroformylation reaction under typical reaction conditions, and olefinic substrates containing functional groups sometimes give poor yields and unexpected products. If there is no plane of symmetry in the substrate across the double bond, at least two isomeric aldehydes are obtained. Although methods for shifting the... 

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