Lanthanide triflates as water-tolerant Lewis acids. Activation of commercial formaldehyde solution and use in the aldol reaction of silyl enol ethers with aldehydes in aqueous media

摘要: Lanthanide trifluoromethanesulfonates (triflates), especially ytterbium triflate (Yb(OTf) 3 ), were found to be stable Lewis acids in water. In the presence of a catalytic amount lanthanide triflate, formaldehyde water solution (commercial solution) was activated and hydroxymethylation reaction silyl enol ethers proceeded smoothly. triflates also quite effective aldol with aldehydes aqueous media; watersoluble such as acetaldehyde, acrolein, chloroacetaldehyde could employed for direct use. Moreover, all these reactions, quantitatively recovered after reactions completed reused