Allyl carbonates hydroformylation

McDonald RI, Wong GW, Neupane RP, Stahl SS, Landis CR (2010) Enantioselective hydroformylation of N-vinyl carboxamides, allyl carbonates, and allyl ethers using chiral diazaphospholane ligands. J Am Chem Soc 132 14027-14029... 

Many organic chemical transformations have been carried out in ionic liquids hydrogenation [4, 5], oxidation [6], epoxidation [7], and hydroformylation [8] reactions, for example. In addition to these processes, numerous synthetic routes involve a carbon-carbon (C-C) bond-forming step. As a result, many C-C bondforming procedures have been studied in ambient-temperature ionic liquids. Among those reported are the Friedel-Crafts acylation [9] and allcylation [10] reactions, allylation reactions [11, 12], the Diels-Alder reaction [13], the Heck reaction [14], and the Suzuld [15] and Trost-Tsuji coupling [16] reactions. 

Hydroformylation - [CARBON MONOXIDE] (Vol 5) - [OXO PROCESS] (Vol 17) -of allyl alcohol [ALLYL ALCOHOL AND MONOALLYL DERIVATIVES] (Vol 2) -catalysts for [CATALYSIS] (Vol 5) -C-19 dicarboxylic acids from [DICARBOXYLIC ACIDS] (Vol 8) -of ethylene [ETHYLENE] (Vol 9) -of ethylene [PROPYL ALCOHOLS - N-PROPYLALCOLHOL] (Vol 20) -of maleate and fumarate esters [MALEIC ANHYDRIDE, MALEIC ACID AND FUMARIC ACID] (Vol 15) -phosphine catalyst [PHOSPHORUS COMPOUNDS] (Vol 18) -platinum-group metal catalysts for [PLATINUM-GROUP METALS] (Vol 19) -rhodium catalysis [PLATINUM-GROUP METALS, COMPOUNDS] (Vol 19) -ruthenium cmpds or catalyst [PLATINUM-GROUP METALS, COMPOUNDS] (Vol 19) -use of coordination compounds [COORDINATION COMPOUNDS] (Vol 7)... 

The insertion of carbon fragments is another common strategy for the synthesis of piperidines. Hydroformylation of an allyl-substituted aminoallylboronate in the presence of a rhodium catalyst produces a reasonable yield of piperidine (Equation 107) <2000H(52)121>. Aldehydes have also been used in the cyclization of imines in a one-pot multistep synthesis of piperidines that allowed further functionalization to take place (Scheme 51) <2003TL8249>. 

The group of Van Leeuwen has reported the synthesis of a series of functionalized diphenylphosphines using carbosilane dendrimers as supports. These were applied as ligands for palladium-catalyzed allylic substitution and amination, as well as for rhodium-catalyzed hydroformylation reactions [20,21,44,45]. Carbosilane dendrimers containing two and three carbon atoms between the silicon branching points were used as models in order to investigate the effect of compactness and flexibility of the dendritic ligands on the catalytic performance of their metal complexes. Peripherally phosphine-functionalized carbosilane dendrimers (with both monodentate... 

Starting from butenediol acetate (28), a further carbon atom is introduced by rhodium-catalyzed hydroformylation, likewise after a copper-catalyzed allyl rearrangement to give vinylglycol diacetate. Splitting of an acetyl group leads to the P-formylcrotyl acetate (8 b) (C5 acetate) 34 a). 

New functionalizing reactions with carbon monoxide to give carbonyl compounds, in addition to hydroformylation, have been developing rapidly during the past ten years, but mainly for laboratory-scale synthesis. Industrial applications of carbon monoxide in the synthesis of fine chemicals have been until now rare. In this section, applications of the carbonylation of benzyl-, aryl-, and related vinyl-and allyl-X compounds are discussed [1]. Emphasis is given especially to a fundamental understanding and to technically interesting developments. 

When allylic and homoallylic alcohols are subjected to hydroformylation, the product was obtained as a lactol, e.g., 3-phenyl-2-hydroxytetrahydrofuran (Scheme 12) [96]. Due to the relative configuration between the C-2 and C-3 carbons, it was formed as a 1 1 diastereomeric mixture. The enantiomeric excesses were determined by oxidizing the lactols into the corresponding lactones. 

The kinetics of the above-mentioned biphasic hydroformylation of allyl alcohol (see Eq. 9) was described by the rate Eq. (15) [10], which shows the inhibition of the reaction rate by the partial pressure of carbon monoxide. 

Cuprous chloride tends to form water-soluble complexes with lower olefins and acts as an IPTC catalyst, e.g., in the two-phase hydrolysis of alkyl chlorides to alcohols with sodium carboxylate solution [10,151] and in the Prins reactions between 1-alkenes and aqueous formaldehyde in the presence of HCl to form 1,3-glycols [10]. Similarly, water-soluble rhodium-based catalysts (4-diphenylphosphinobenzoic acid and tri-Cs-io-alkylmethylam-monium chlorides) were used as IPTC catalysts for the hydroformylation of hexene, dodecene, and hexadecene to produce aldehydes for the fine chemicals market [152]. Palladium diphenyl(potassium sulfonatobenzyl)phosphine and its oxide complexes catalyzed the IPTC dehalogenation reactions of allyl and benzyl halides [153]. Allylic substrates such as cinnamyl ethyl carbonate and nucleophiles such as ethyl acetoactate and acetyl acetone catalyzed by a water-soluble bis(dibenzylideneacetone)palladium or palladium complex of sulfonated triphenylphosphine gave regio- and stereo-specific alkylation products in quantitative yields [154]. Ito et al. used a self-assembled nanocage as an IPTC catalyst for the Wacker oxidation of styrene catalyzed by (en)Pd(N03) [155]. 

In rhodimn catalyzed hydroformylation the effect is less drastic and often remains imobserved, but surely diene impurities obscure the kinetics of alkene hydroformylation [42]. Because the effect is often only temporary we summarize it here under dormant sites . Hydroformylation of conjugated alkadienes is much slower than that of alkenes, but also here alkadienes are more reactive tiian alkenes toward rhodium hydrides [43, 44]. Stable tc-allyl complexes are formed that undergo very slowly insertion of carbon monoxide (Figure 17). The resting state of the catalyst wBl be a Ji-allyl species and less rhodium hydride is available for alkene hydroformylation. Thus, alkadienes must be thoroughly removed as described by Garland [45], especially in kinetic studies. It seems likely that 1,3- and 1,2-diene impurities in 1 -alkenes will slow down, if not inhibit, the hydroformylation of alkenes. 

Very often, the kinetics of rhodium-catalyzed hydroformylation do not follow the expected first order in alkene concentration and the minus one order in GO pressure. Severe or slight incubation has also been observed. To those skilled in the art, it is known that impurities such as 1,3-alkadienes, enones, and terminal alkynes may be the cause of such behavior. In a mixture of 1-alkenes and butadiene for instance, the latter is much more reactive and will react preferentially with the rhodium hydride catalyst. The allylic rhodium species formed, however, reacts much more sluggishly with carbon monoxide than alkyl rhodium complexes, and thus the catalyst is tied up in this inactive sink. 

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