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

被引:397
作者
KOBAYASHI, S
HACHIYA, I
机构
[1] Department of Applied Chemistry, Faculty of Science, Science University of Tokyo (SUT), Tokyo 162, Kagurazaka, Shinjuku-ku
关键词
D O I
10.1021/jo00092a017
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
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 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.
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页码:3590 / 3596
页数:7
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