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
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
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DOI：
10.1021/jo00092a017
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发表时间：
1994-07-01
影响因子：
3.6
通讯作者：
HACHIYA, I
中科院分区：
文献类型：
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作者：
KOBAYASHI, S;HACHIYA, I
镧系三氟甲烷磺酸盐（三氟磺酸盐），特别是三氟酸钇(Yb(OTf)(3))，在水中是稳定的路易斯酸。在一定催化量的三氟化镧存在下，水溶液（商用甲醛溶液）中的甲醛被活化，硅烯醇醚的羟甲基化反应顺利进行。三氟化镧在硅烯醚与醛的醛缩反应中也很有效，水溶性醛如乙醛、丙烯醛和氯乙醛可直接使用。此外，在所有这些反应中，三氟化镧在反应完成后都可以定量回收，并且可以重复使用。
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.