Allyl acetate, hydroformylation

Industrial (BASF) syntheses of vitamin A and vitamin A aldehyde have been accomplished utilizing the aldehydes obtained from allyl acetate hydroformylation.22 Either aldehyde (10) or (11) reacts with the same phosphorus ylide to give vitamin A or retinal (Scheme 4). Hydroformylation of 3-methyl-2-butenyl acetate gives a high yield of 2-formyl-3-methylbutyl acetate. Elimination of acetic acid followed by isomerization provides trimethylacrylaldehyde, which is an intermediate in the synthesis of irones (Scheme 5). 

Another route to the diol monomer is provided by hydroformylation of allyl alcohol or allyl acetate. Allyl acetate can be produced easily by the palladium-catalyzed oxidation of propylene in the presence of acetic acid in a process similar to commercial vinyl acetate production. Both cobalt-and rhodium-catalyzed hydroformylations have received much attention in recent patent literature (83-86). Hydroformylation with cobalt carbonyl at 140°C and 180-200 atm H2/CO (83) gave a mixture of three aldehydes in 85-99% total yield. 

Allyl alcohol may be a preferred olefin for rhodium hydroformylation routes to 1,4-butanediol. Comparison of allyl acetate and allyl alcohol as... 

Both homogeneous and heterogeneous procedures have been developed for the synthesis of allyl acetate from propene (equation 137 and Table 6). Allyl acetate is an interesting intermediate which can be hydrolyzed to allyl alcohol,424 or hydroformylated to a 1,4-butanediol or THF precursor.425... 

The hydroformylation of ally and vinyl acetals yields some useful intermediates. Allyl acetate undergoes partial double bond migration prior to hydroformylation with a cobalt catalyst in the absence of phosphine (equation 20).2-5 Rhodium catalysts containing chelating phosphines are more selective to the linear aldehyde.31... 

Platinum complexes, [PtCl2 (l ,l )-XantBino ] (2) and its S,S analogue, were treated with tin(II) chloride to form the pre-catalyst for chemo-, regio-, and enantio-selective hydroformylation of styrene, vinyl acetate and allyl acetate. Although the reaction showed good chemo- and regio-selectivities, only moderate ee was obtained.103... 

Allyl acetate can also be hydroformylated, yielding the monoacetate of 1,4-butanediol, which is then hydrolysed. 

Depending on the ligand used, allyl acetate produces either the branched or the linear product [79]. Hydroformylation of isomeric butenyl-diacetates with... 

Abstract Aldehydes obtained from olefins under hydroformylation conditions can be converted to more complex reaction products in one-pot reaction sequences. These involve heterofunctionalization of aldehydes to form acetals, aminals, imines and enamines, including reduction products of the latter in an overall hydroaminomethylation. Furthermore, numerous conversions of oxo aldehydes with additional C.C-bond formation are conceivable such as aldol reactions, allylations, carbonyl olefinations, ene reactions and electrophilic aromatic substitutions, including Fischer indole syntheses. 

Very recently the tandem hydroformylation/acetalization has been used for the synthesis of new synthetically valuable chiral auxiliary derived from camphor. Stereoselective allylation of camphor and subsequent terminal hydroformylation of the resulting homoallylic alcohol affords the 5-lactol auxiliary (camTHP OH) in multigram scale (Scheme 8) [41]. 

Pd-catalyzed allylic amination of crotyl acetate by piperidine, while exhibiting a reduced rate as is commonly observed for heterogenized systems (90% conversion achieved after 30 min compared with 5 min for the homogeneous system). Interestingly, the catalyst could be recycled three times via a simple filtration step. Subsequently, the catalyst was separated from the support and the support was uploaded with hydroformylation catalysts. 

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). 

An early attempt to hydroformylate butenediol using a cobalt carbonyl catalyst gave tetrahydro-2-fiiranmethanol (95), presumably by allylic rearrangement to 3-butene-l,2-diol before hydroformylation. Later, hydroformylation of butenediol diacetate with a rhodium complex as catalyst gave the acetate of 3-formyl-3-buten-l-ol (96). Hydrogenation in such a system gave 2-methyl-1,4-butanediol (97). 

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