Catalytic Methanol Coupling Achieved

Methanol is a high-volume chemical feedstock and thus a readily available reagent. But its ability to react at carbon rather than oxygen in chemical synthesis is limited—it’s restricted primarily to the Monsanto and Cativa processes for carbonylating methanol to form acetic acid. Michael J. Krische and coworkers of the University of Texas, Austin, have now developed iridium complexes that catalyze the direct C–H functionalization of methanol with allenes to form higher alcohols bearing a quaternary carbon center (Nat. Chem., DOI: 10.1038/nchem.1001). The regioselective hydrohydroxymethylation process does not generate stoichiometric by-products. “Methanol is not an obvious choice of reagent for C–C bond formation, and it is a clever hydrogen-transfer sequence combined with a highly reactive catalyst that has allowed Krische and coworkers to make this significant advance,” comments carbon-coupling expert Jonathan M. J. Williams of the University of Bath, in England. Krische notes that his group hopes to advance the work further by developing “related alcohol C–C couplings applicable to renewable feedstocks, such as the coupling of glycerol to α-olefins.”