Allyl acetate, telomerization

The acyclic carbon framework was derived from Tsuji s previous work on the telomerization of butadiene. Thus allylic acetate 60 was converted to the related allylic chloride and the carbonyl was reduced to give 91 in good yield. 

Palladium(O)-catalyzed reactions ofallenic dienes 37 in acetic acid afforded allylic acetates 38 (Scheme 11.6) [52]. This reaction is reminiscent of telomerizations, and a mechanism via a palladacycle rearranging to a Tt-allyl complex was inferred as being likely. A pathway via a palladium hydride can, however, not be excluded. 

From a mechanistic point of view the first steps of the catalytic cycle should be similar to the telomerization of butadiene itself (Scheme 2). The catalytic precursor generates the Pd(0) species A that reacts to the bis-(ri -allyl) complex C. The C,C bond formation between two C4 units is followed by insertion of carbon dioxide into a Pd,C bond affording the carboxylate intermediate D. Different pathways have been discussed to describe the multiple product formation (refer to ). Interestingly, a bis-(carboxylato) complex may be prepared directly from the reaction of lactone 1, palladium acetate and P(i-Pr)3. This complex was structurally characterized by Behr and co-workers and shows good activity as catalyst. Reviewing the literature, there are some remarkable facts and open questions of theoretical and technical interest ... 

Palladium(I) intermediates have been proposed for the telomerization of butadiene with acetic acid yielding acetoxyoctadienes, and in a recent review the involvement of Pd(I) has been snggested for processes in which Pd(II) had been formerly suggested. These processes include alkene isomerization, methoxycarbonylation of alkynes to acrylic esters, and the aryloxycarbonylation of allyl alcohol. 

Full details of the Ni - and Pd -catalysed telomerization reactions of butadiene with phenylhydrazones (see Volume 6, p. 388) have now been published. Reaction of butadiene with diethylamine gives (49 Z = NEta) in the presence of allyl M halides. The catalytic activity increases in the series M = Ni < M = Ptsimilar reactions of butadiene, especially virith cyclic secondary amines (e.g. morpholine). For M = Pd addition of AcOH improves the yield of (49 Z = NEta) whilst for M = Pt no telomers are formed in the absence of Al(OR)3 (R = Pr or Bu ) co-catalysts. The reaction of butadiene with acetic acid to give (49 Z = OAc) is also catalysed by [M(cod)2] although with the catalyst M = Pd l-vinylhex-5-enyl acetate is a by-product (20%). Reactions of butadiene with acetaldehyde and phenyl isocyanate in the presence of [Pd(cod)t]-2PPh3 give (50 and (51), respectively, ... 

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