Study On Tandem Organic Reactions Catalyzed By Lanthanide Halides

Tandem organic reactions catalyzed by lanthanide halides were studied in this thesis the followings are composed: 1. SmI2 can effectively catalyze the condensation of o-phenylenediamine and ketones affording the corresponding 1,5-benzodiazepines in moderate to excellent yields under very mild and solvent-free conditions. The real active species here was suggested to be a Sm(III) intermediate formed in situ and the mechanism of the present reaction was proposed. 2. YbCl3 is found to be a simple and efficient catalyst for the one-pot reactions of aldehydes, amines and dialkyl phosphites to afford α-amino phosphonates in moderate to excellent yields under mild conditions. Moreover, the catalyst is water-tolerant and could be recovered and reused. 3. The tandem reaction starting from fructose was explored by use of YbCl3 as a catalyst. Fructose was first dehydrated forming 5-hydroxymethyl-2-furaldehyde as an intermediate, which was directly treated by aniline and diethyl phosphite to give the corresponding a-amino phosphonate.