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
作者:Shu Kobayashi、Iwao Hachiya
DOI:10.1021/jo00092a017
日期:1994.7
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 of lanthanide triflate, formaldehyde in water solution (commercial formaldehyde solution) was activated and the hydroxymethylation reaction of silyl enol ethers proceeded smoothly. Lanthanide triflates were also quite effective in the aldol reaction of silyl enol ethers with aldehydes in aqueous media, and water-soluble aldehydes such as acetaldehyde, acrolein, and chloroacetaldehyde could be employed for direct use. Moreover, in all these reactions, lanthanide triflates were quantitatively recovered after the reactions were completed and could be reused.
The Aldol Reaction of Silyl Enol Ethers with Aldehydes in Aqueous Media
作者:Shū Kobayashi、Iwao Hachiya
DOI:10.1016/s0040-4039(00)91691-5
日期:1992.3
The aldol reaction of silyl enol ethers with aldehydes is successfully carried out in aqueous media by using a lanthanide trifluoromethanesulfonate as a catalyst. Water soluble aldehydes are applicable and the catalyst can be recovered and reused in this reaction.
Stabilization of reactive aldehydes by complexation with methylaluminum bis(2,6-diphenylphenoxide) and their synthetic application
作者:Keiji Maruoka、Arnel B. Concepcion、Noriaki Murase、Masataka Oishi、Naoki Hirayama、Hisashi Yamamoto
DOI:10.1021/ja00063a013
日期:1993.5
Reactive aldehydes such as formaldehyde and α-chloro aldehydes can be successfully generated by treatment of readily available trioxane and α-chloro aldehyde trimers, respectively, with methylaluminum bis(2,6-diphenylphenoxide) (MAPH), and stabilized as their 1:1 coordination complexes with MAPH. The resulting CH 2 =O.MAPH complex reacts with a variety of olefins to furnish ene-reaction products with