Use of Iridium‐Catalyzed Transfer Vinylation for the Synthesis of Bio‐Based (bis)‐Vinyl Ethers

The iridium catalyzed transfer vinylation of bio-based polyols and of other alcohols and phenols with interesting structural motifs was accomplished with vinyl acetate in 2-MeTHF as a green solvent. The optimized synthetic procedure has as main advantages the use of catalytic instead of stoichiometric amounts of base and high selectivities towards the formation of bis-vinyl ethers as a result of the suppression of the acetal formation reaction that typically occurs in the vinylation of diols. In addition, the thermodynamically preferred transesterification reaction leading to the acetate esters and bis-esters was completely suppressed. DFT calculations revealed an iridium-acetate complex as the active catalytic species and they disclosed the importance of the carbonyl group of vinyl acetate for the formation of a six-membered cyclic intermediate.