Catalytic C-N And C-C Bond Formation By Lanthanide Or Alkali Metal Complex

Rare-earth metal amides were used in catalyzing three-component reaction of amines,epoxides,and carbonates to produce oxazolidinones,and alkali metal salt was used to catalyze the reaction of terminal alkynes with carbodiimides to generate amidines.Main results were as follows:1.The catalytic performance of easily available rare-earth metal amides in three-component reaction of amines,epoxides,and carbonates was investigated,and the optimal conditions were confirmed as follows:2 mol%of La(μ-C1)Li[(Me3Si)2N]3(THF)3 as catalyst,neat,80℃,12 h reaction time.This system was equipped with good generality,and a wide range of aromatic and aliphatic amines,as well as mono-substituted epoxides were converted into 47 oxazolidinones in 13-97%yields,while increasing the catalyst loading led to improve yields in reactions of disubstituted epoxides.Two possible reaction pathways through intermediates of β-amino alcohols or amides were suggested.In conclusion,this catalytic system had some advantages,such as simple starting materials and neat condition,especially was applicable to aliphatic amines.2.The addition reaction of terminal alkynes to carbodiimides catalyzed by alkali metal salt was explored,and the optimal reaction conditions were 2 mol%of Cs2CO3 as catalyst,DMSO as solvent,60℃,6 h reaction time.Phenylacetylenes bearing either electron-donating or withdrawing groups,and heterocyclic acetylenes could be converted straightforwardly into 12 amidines in yields of 87-95%.In contrast,the catalytic system was equipped with a cheap and stable catalyst of Cs2CO3,and simple experimental operation,instead of complicated and air-sensitive catalysts.