Isomerizing-Hydroboration of the Monounsaturated Fatty Acid Ester Methyl Oleate

Abstract

Biodiesel fuel, a mixture of fatty acid methyl esters (FAMEs) derived from plant oils, is increasingly available as a chemical feedstock. Methyl oleate (18:1), the 18-carbon monounsaturated FAME, is shown to undergo [Ir(COE) 2 Cl] 2 /dppe-catalyzed hydroboration with pinacolborane to give the product (7) in which the boronate ester group is in the terminal (C18) position. The formation of this product shows that the catalyst promotes both (1) the isomerization of the double bond from the 9,10-position of 18:1 to the terminal position and (2) the selective hydroboration of this isomer to give the product (7) in 45% yield. This tandem reaction should be capable of converting all isomers of 18:1 into the same product 7. † This paper is dedicated to Professor Jiabi Chen, Shanghai Institute of Organic Chemistry, on the occasion of his retirement and 65th birthday with thanks for his many contributions to organometallic chemistry.

Regioselective Synthesis of β‐Aryl‐ and β‐Amino‐Substituted Aliphatic Esters by Rhodium‐Catalyzed Tandem Double‐Bond Migration/Conjugate Addition

“…This corresponds well with the findings of Angelici et al [5] In combination with the characteristic shape of the chromatogram, the value of this integral was used to evaluate whether equilibrium had been reached.…”

“…Isomerization studies: In search of a catalyst system that is capable of promoting both isomerizations and conjugate additions, we investigated various homogeneous isomerization catalysts including [PtCl 6 5 ], RhCl 3 ·3 H 2 O, and several rhodium(I) complexes (see Table 1). We first evaluated their activity in catalyzing double-bond migrations in the presence of ester groups, and then probed which of the active catalysts also mediates the addition of carbon nucleophiles to Michael systems.…”

“…Thus, Angelici et al reported an isomerizing hydroboration of fatty esters selectively at the terminal position in the presence of an iridium catalyst (A, Scheme 2). [5] Behr et al described the synthesis of linear aldehydes from internally unsaturated fatty esters under hydroformylation conditions by using a rhodium catalyst bearing a sterically demanding phosphite ligand (B). [6] A palladium-based catalyst system was used to convert olefinic fatty acids and alcohols into dialkyl dicarboxylates by isomerizing alkoxycarbonylation (C).…”

Hydroboration of Methyl Esters of Fatty Acids

“…Carbon NMR confirmed these results with the presence a new CH2B signal at 22.68 ppm (Ghebreyessus & Angelici, 2006).…”

Fette und Öle als nachwachsende Rohstoffe in der Chemie

“…34 % (Schema 10); [89] 10). [91] Neue biobasierte Polyole wurden durch Hydroformylierung von 1 b und einigen nativen Ölen in Gegenwart homogener Rhodiumkatalyatoren erhalten. [92][93][94][95] Homogene Rhodiumkomplexe wurden des Weiteren für die Hydroaminomethylierung von Alkenen eingesetzt.…”