Telomerisation of 1,3-butadiene with 1,4:3,6-dianhydrohexitols: an atom-economic and selective synthesis of amphiphilic monoethers from agro-based diols.

The telomerisation of 1,3-butadiene with a Pd/TPPTS catalytic system in water or an organic solvent was used for the synthesis of C8 ethers from isosorbide, an agro-based diol. The use of water/oil biphasic reaction conditions allowed the selective synthesis of monoethers with improved rates upon using inorganic bases as promotors. As isosorbide is a non-symmetric diol, the two hydroxyl groups display different reactivities. 2-O-substituted-monoethers were preferentially obtained if water was used as the solvent, whereas in DMSO 5-O-substituted monoethers were the major products. Complete conversions of isosorbide with up to 94% monoether selectivities were obtained. The optimized reaction conditions were successfully applied to isomannide and isoidide for the selective synthesis of the derived ethers. An improved reactivity of the endo-hydroxy groups of isosorbide and isomannide versus the exo-hydroxy groups of isosorbide and isoidide was observed if the reaction was performed in DMSO instead of water.