Metathesis of unsaturated fatty acids: Synthesis of long-chain unsaturated-α,ω-dicarboxylic acids

Article abstract of DOI:10.1007/s11746-006-1249-0

The self-metathesis of readily available monounsaturated FA has the potential of being an important pathway for the synthesis of symmetrical long-chain unsaturated-α,ω-dicarboxylic acids (C₁₈-C ₂₆). Previous studies on the self-metathesis of monounsaturated FA esters using ruthenium catalysts in solution, however, suffered from low conversions as a result of the thermodynamic control of the reaction. We have found that the secondgeneration Grubbs catalyst can effectively catalyze the solventfree self-metathesis of monounsaturated FA of varying purity (from 90 to 99%) to afford two important products-monounsaturated dicarboxylic acids and hydrocarbons-in very high molar conversions (>80%). This solvent-free self-metathesis reaction also works for monounsaturated FA containing additional functional groups. Reactions were conducted at catalyst loadings as low as 0.005 mol%, and turnover numbers as high as 10,800 could be obtained. This discovery represents an attractive approach to the large-scale production of useful monounsaturated-α,ω-dicarboxylic acids and long-chain unsaturated hydrocarbons by means of this solvent-free ruthenium-catalyzed self-metathesis of readily available monounsaturated FA. Copyright