The cross-metathesis of methyl oleate with cis-2-butene-1,4-diyl diacetate and the influence of protecting groups

Abstract

Summary Background: α,ω-Difunctional substrates are useful intermediates for polymer synthesis. An attractive, sustainable and selective (but as yet unused) method in the chemical industry is the oleochemical cross-metathesis with preferably symmetric functionalised substrates. The current study explores the cross-metathesis of methyl oleate (1) with cis-2-butene-1,4-diyl diacetate (2) starting from renewable resources and quite inexpensive base chemicals. Results: This cross-metathesis reaction was carried out with several phosphine and N-heterocyclic carbene ruthenium catalysts. The reaction conditions were optimised for high conversions in combination with high cross-metathesis selectivity. The influence of protecting groups present in the substrates on the necessary catalyst loading was also investigated. Conclusions: The value-added methyl 11-acetoxyundec-9-enoate (3) and undec-2-enyl acetate (4) are accessed with nearly quantitative oleochemical conversions and high cross-metathesis selectivity under mild reaction conditions. These two cross-metathesis products can be potentially used as functional monomers for diverse sustainable polymers.

Cross metathesis of bio-sourced fatty nitriles with acrylonitrile

“…Functional allylic partners such as allylic halide [25][26] or acetate [27][28] have also been used to introduce a reactive allylic functionality at the end of a fatty carbon chain. Another important cross metathesis partner that allows further transformation into amines is acrylonitrile [29].…”

Ethenolysis: A Green Catalytic Tool to Cleave Carbon–Carbon Double Bonds

“…Among them, the sequence involving several olefin metathesis transformations can be highlighted. Self‐metathesis produces diesters and cross‐metathesis with a variety electron‐deficient alkenes, such as acrylates and equivalents, acrolein, acrylonitrile, allyl chloride, allyl acetate, but‐3‐enenitrile, or pent‐4‐enenitrile, provides useful α,ω‐bifunctional polymer precursors (Scheme ). Metathesis not only with double bonds but also with triple bonds makes possible a straightforward access to long‐chain conjugated dienes that cannot be produced from internal linear olefins …”

Metathesis applied to unsaturated lipid compounds

“…Both products can be used in the manufacture of polymers or polyallyl alcohols. Under mild reaction conditions (1 mol% catalyst, 508C, 5 h) with a fat/substrate ratio of 1/8 almost quantitative conversions of the fatty substrate with high yields are possible [5].…”