The Palladium‐Catalyzed Carboxytelomerization of Butadiene with Agrobased Alcohols and Polyols

Abstract

The palladium catalyzed carboxytelomerization reaction of alcohols with butadiene allows for efficient and atom‐economical access to unsaturated alkyl nona‐3,8‐dienoate esters. The study focused on the nature of the catalyst (phosphine and acid) with ethanol. Commercially available triarylphosphines and carboxylic acids associated with a simple palladium precursor appear to be the best combination for in situ generation of the catalyst. The reaction conditions were further optimized and the carboxytelomerization reaction was efficiently applied to the full transformation of several industrially relevant agro‐based monoalcohols and polyols.

Palladium Catalysed Acid‐Free Carboxytelomerisation of 1,3‐Butadiene with Alcohols Accessing Pelargonic Acid Derivatives Including Triglycerides under Selectivity Control

“…Surprisingly, further elongation of the carbon chain length as in 1,7‐heptandiol 2 n results in an increasing yield of the diester 4 n in 85% (entry 7). The same effect of increasing yield by elongation of the chain length, except for elongation of ethylene glycol, is observed in the study on the carboxytelomerisation with benzoic acid as additive . Elongation of the carbon chain length results in a reduction of nucleophilicity and therefore in a loss of yield, although nucleophilicity is more decreased through elongation from two to three carbon atoms than through further elongation.…”

“…[18] Elongation of the carbon chain length results in a reduction of nucleophilicity and therefore in a loss of yield, although Table 2. UPDATES asc.wiley-vch.de length as in 1,7-heptandiol 2 n results in an increasing yield of the diester 4 n in 85% (entry 7).…”

“…In a carboxytelomerisation it is conceivably converted to a mono-, di-or triester, which are all of interest due to the odd number of carbon atoms in the unsaturated pelargonic acid ester group that does not occur in nature. [23,24] Whereas the conversion of glycerol to the triglyceride has recently been reported by the use of an acidic catalytic system, [18] the monoester was not synthesised selectively, although especially the monoglyceride could be industrially relevant as nonionic surfactant. Pelargonates are generally effective cohesive agents, [21] lubricants.…”

“…In theory, depending on the employed alcohol and 1,3diene, a vast array of unsaturated products with high potential for industrial applications can be obtained through the carboxytelomerisation. [18] By converting 1,3-butadiene with further alcohols of different characteristics according to sterical demands, chain length and nucleophilicity, we are not only able to widen the range of novel C 9 -acid esters that are potentially applied as, for instance, plastic monomers, lubricants and surfactants but uncover limitations and control selectivity towards mono-and polyesters of the carboxytelomerisation with an acidfree system. [14,15] Besides the variation in the used 1,3-diene, also an application of several alcohols is subject of research in terms of carboxytelomerisation.…”

“…The same catalyst system comprising palladium acetate, triphenyl phosphine and benzoic acid was successfully applied for a broad range of agro‐based monoalcohols derived from glycerol modified with protective groups. Furthermore, monoalcohols based on pentoses and polyols with up to four hydroxyl groups were converted to the corresponding esters in up to 94% yield …”