Cross-metathesis of oleyl alcohol with methyl acrylate: optimization of reaction conditions and comparison of their environmental impact

Abstract

The synthesis of a,w-difunctional monomers from the renewable resource oleyl alcohol via a cross-metathesis reaction with methyl acrylate is described. The reaction conditions were optimized for high conversions in combination with high cross-metathesis selectivity. The introduction of a protecting group for the alcohol functionality of oleyl alcohol was found to be a necessary step in order to significantly reduce the amount of metathesis catalyst required to obtain full conversions and good selectivities. All reaction conditions were compared to each other in a quantitative fashion with the program EATOS (environmental assessment tool for organic syntheses) revealing the environmentally most benign approach for the synthesis of the desired a,w-difunctional monomers. These calculations also clearly revealed that the introduction of the protecting group was a necessary step in order to minimize the amount of the produced waste and to use the raw materials more efficiently.

Alkene Metathesis Catalysis: A Key for Transformations of Unsaturated Plant Oils and Renewable Derivatives

“…Catalyst IV was also the most efficient for the reaction of 8 ([8] = 0.1 M) with 4 equivalents of acrylonitrile in toluene at 100°C for 1 h. With 5 mol% of catalyst the nitrile ester 12 was obtained (86%) as a mixture of Z (major) and E isomers (2.9/1) with a small amount of C10 ester with a terminal double bond [52]. Thus the cross-metathesis with acrylonitrile of alkenes containing an internal double bond can be efficiently achieved, as it was also possible with acrylic esters [16,17]. Using syringe pump addition of catalyst IV at 100°C for 5 h, the unsaturated nitrile ester 10 was obtained in 88% yield, with high TON of 1960 [53].…”

“…In some examples it was shown that acrylonitrile inhibits the ruthenium-catalysed cross-metathesis of functional alkenes, whereas methyl acrylate does not inhibit this reaction as some cross-metathesis can be performed in bulk in methyl acrylate [16,17,[70][71][72]. Thus, it appeared that the linear amino ester 18 could also arise from the cross-metathesis of the 10-undecenenitrile 21 with methyl acrylate followed by hydrogenation.…”

“…Vegetable oils by transesterification easily release unsaturated fatty esters which offer, via cross-metathesis with alkenes, selective access to terminal alkenes or bifunctional internal olefins that are crucial intermediates for industry. Thus catalytic crossmetathesis has become a key to reveal the potential of renewable plant oils or natural terpenes [11][12][13][14][15][16][17][18].…”

Fette und Öle als nachwachsende Rohstoffe in der Chemie

“…[121] Auch die KM von Fettalkoholen wurde untersucht. Dabei wurden ungewollte Nebenreaktionen, geringe Umsätze sowie schlechte Selektivität beobachtet, [122] wahrscheinlich weil Alkohole Ruthenium-Metathesekatalysatoren zersetzen können. [123] Um dies zu umgehen, wurden die gewünschten w-Hydroxyfettsäureester mittels KM von acetatgeschützten Fettalkoholen mit Methylacrylat in einer effizienten katalytischen Reaktion hergestellt.…”

“…[123] Um dies zu umgehen, wurden die gewünschten w-Hydroxyfettsäureester mittels KM von acetatgeschützten Fettalkoholen mit Methylacrylat in einer effizienten katalytischen Reaktion hergestellt. [122] Im Gegensatz hierzu war die Schutzgruppenstrategie bei der KM von 5 b nicht erforderlich (Schema 15), was darauf hindeutet, dass sekundäre Alkohole von den unterSchema 11. Hydroaminomethylierung von 1 c mit Morpholin.…”