From Carboxytelomerization of 1,3‐Butadiene to Linear α,ω‐C₁₀‐Diester Combinatoric Approaches for an Efficient Synthetic Route

Abstract

Two novel reaction pathways were tested to synthesize the linear α,ω-C -diester exclusively from three basic reagents: 1,3-butadiene, carbon monoxide and methanol. Therefore, carboxytelomerization of 1,3-butadiene and methanol was merged with methoxycarbonylation in two different ways to obtain highly linear C -diester. Through a palladium-based and -assisted tandem catalytic system, 22 % yield of the desired C -diester was obtained without isolating the intermediates. Subsequently, the limitations of the novel assisted tandem catalytic concept were uncovered and based on that, a two-step reaction regime was established. By optimization of the carboxytelomerization, the C -monoester as intermediate could be formed in nearly quantitative yields and excellent linearity. In a second reaction step, the isolated monoester was successfully converted by methoxycarbonylation into the desired linear C -diester in overall yields up to 84 %.

The Telomerization of 1,3‐Dienes – A Reaction Grows Up

“…The catalytic system needed to be modified to Pd/P(O‐ i ‐Pr) 3 without pyridine for the assisted tandem‐catalyzed reaction. Acid treatment after the first step still leads to a 22% yield . This reaction can also be carried out using more complex alcohols, for example lignin‐type phenols or even Kraft‐Lignin .…”

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

“…[6] This carbonylative version of the telomerizationreaction [7] encompasses severala dvantagess uch as high atom-economy and the use of industrially accessible reactants (e.g.,b utadiene, CO, alcohols). [11] We recently reported that the reaction can be ef-The palladium catalyzedc arboxytelomerization reactiono fa lcohols with butadiene allows for efficient and atom-economical access to unsaturated alkyl nona-3,8-dienoate esters. [8] Moreover, the butadiene coupling reactions advantageously lead to the formation of two unsaturations and thus open the way to further functionalization.…”

Homogeneously Catalyzed 1,3‐Diene Functionalization – A Success Story from Laboratory to Miniplant Scale

“…In the first reaction step, the C9‐monoester as intermediate was quantitatively generated by an optimized palladium‐catalyzed carboxytelomerization ( vide infra for more details on carboxytelomerization). Subsequently, the monoester was isolated by distillation and converted to the C 10 ‐diester in 84 % yield by sequential methoxycarbonylation …”

“…Recently, we have shown that an excess of 1,3‐butadiene increases the stability of the catalyst resulting in quantitative yields of the target product. Moreover, we established a reaction protocol for the synthesis of α,ω ‐diesters as polymer precursors by using a merger of carboxytelomerization and subsequent methoxycarbonylation yielding in 86 % of the linear C 10 ‐diester …”