Dehydrogenative alcohol coupling and one-pot cross metathesis/dehydrogenative coupling reactions of alcohols using Hoveyda-Grubbs catalysts

In this study, in situ formed ruthenium hydride species that were generated from Grubbs type catalysts are used as efficient catalysts for dehydrogenative alcohol coupling and sequential cross-metathesis/dehydrogenative coupling reactions. The selectivity of Grubbs first generation catalysts (G1) in dehydrogenative alcohol coupling reactions can be tuned for the ester formation in the presence of weak bases, while the selectivity can be switched to the beta-alkylated alcohol formation using strong bases. The performance of Hoveyda-Grubbs 2nd generation catalyst (HG2) was improved in the presence of tricyclohexylphosphine for the selective synthesis of ester derivatives with weak and strong bases in quantitative yields. Allyl alcohol was used as self and cross-metathesis substrate for the HG2 catalyzed sequential cross-metathesis/dehydrogenative alcohol coupling reactions to obtain gamma-butyrolactone and long-chain ester derivatives in quantitative yields.

Automated summary

In this study, in situ formed ruthenium hydride species from Grubbs type catalysts were used as efficient catalysts for dehydrogenative alcohol coupling and sequential cross-metathesis/dehydrogenative coupling reactions. The selectivity of the catalysts can be tuned by using different bases to obtain different products. With the presence of a new ligand, the performance of the catalyst was significantly improved, yielding products in quantitative yields.