Mischmetall, an alloy of the light lanthanides, has been used in a variety of organicreactions, either as a coreductant in samarium(II)-mediated reactions (Barbier and Grignard-type reactions, pinacoliccouplingreactions) or as the promoter of Reformatsky-type reactions. It has been also employed as the starting material for easy syntheses of lanthanide trihalides, the reactivity of which has been
Direct construction of a quaternary carbon center utilizing an organosamarium reagent
作者:Zhifang Li、Yongmin Zhang
DOI:10.1016/s0040-4039(01)01831-7
日期:2001.11
Direct geminal diallylation of lactams and acyclic amides containing an NH bond has been achieved in the presence of allylsamarium bromide. By applying this method, quaternary carbons have been constructed, and 2,2-diallylatednitrogenheterocycles and diallylated amides were synthesized in moderate to good yields under mild conditions.
Direct construction of quaternary carbon center utilizing an allylsamarium bromide reagent
作者:Zhifang Li、Yongmin Zhang
DOI:10.1016/s0040-4020(02)00491-x
日期:2002.6
Direct geminal diallylation of lactones, lactams and acyclic amides containing a N–H bond has been achieved in the presence of allylsamarium bromide. By applying this method, quaternary carbons have been constructed, and 2,2-diallylated cyclic ethers, 2,2-diallylatednitrogenheterocycles and diallylated amides were synthesized in moderate to good yields under mild conditions.
Allylation of carbonylcompounds (aldehydes, ketones, esters, lactones, acid anhydrides) proceeds smoothly at room temperature by the reaction of a carbonylcompound, an allylic benzoate or allylic phenyl ether, diethylzinc, and a catalytic amount of Pd(0)-complex in THF under N2.
achieved by the use of samarium diiodide in catalytic amounts together with mischmetall (an alloy of the light lanthanides) as a coreductant. Plausible catalytic schemes are proposed. In addition, organocerium and -lanthanum reagents have been obtained from samarium diiodide catalysed reactions between organic halides and cerium or lanthanum metal, giving a newroute to organolanthanoid compounds. It also