Mechanistic insights into the Pt(II)-catalyzed rearrangements from homopropargylic alcohols to furans: Hydrogen vs tert-butyldimethylsilyl group migrations

•The methoxy group is the optimal leaving group.•Si-migration is favored in toluene while H-migration is favored in THF.•We proposed a H2O and Cl co-aided H-migration mechanism in THF.

By carrying out B3LYP calculations, we have performed a detailed mechanism study on the reaction of platinum catalyzed rearrangements of homopropargylic alcohols derivatives into isomeric polysubstituted furans in THF and toluene solutions, respectively. The reaction steps include α,β-unsaturated carbene complex formation, and H atom or Si (Si = tert-butyldimethylsilyl) group migration. In the step of α,β-unsaturated carbene complex formation, the methoxy group is the optimal leaving group. Our calculations are consistent with the experimental results that Si-migration is favored in toluene while H-migration is favored in THF. Based on the Cl-aided H-migration mechanism postulated by Ferreira et al., we proposed a H2O and Cl co-aided H-migration mechanism in THF, in which H2O and Cl both act as the medium to transfer H.

Graphical abstractA theoretical study on the mechanism of platinum catalyzed rearrangements of homopropargylic alcohols derivatives into isomeric polysubstituted furan. Figure optionsDownload full-size imageDownload as PowerPoint slide