Preparation of Axially Chiral (Racemic) Spirosilanes and Spirogermanes by Selective Spirozirconation
摘要:
Chiral (racemic) functional spirosilanes or -germanes, containing two (or four) stereogenic centers, were synthesized by selective cyclozirconation (or spirozirconation) of di- and tetraallylsilanes and di- and tetraallylgermanes.
Scandium trifluoromethanesulfonate-catalyzed chemoselective allylation reactions of carbonyl compounds with tetraallylgermane in aqueous media
作者:Takahiko Akiyama、Junko Iwai、Megumi Sugano
DOI:10.1016/s0040-4020(99)00371-3
日期:1999.6
Scandium(III) triflate-catalyzed allylation of carbonylcompounds with tetraalylgermane proceeded readily in aqueous nitromethane to afford homoallyl alcohols in excellent to good yields. The presence of H2O is indispensable for the allylation of aldehydes to proceed smoothly. Aldehydes were allylated highlychemoselectively in the presence of ketone moieties.
Reactivity of dianionic hexacoordinate germanium complexes toward organometallic reagents. A new route to organogermanes
作者:G. Cerveau、C. Chuit、R. J. P. Corriu、C. Reye
DOI:10.1021/om00051a049
日期:1991.5
Lithium and potassium tris(benzene-1,2-diolato)germanates (2a and 2b, respectively) and potassium tris(butane-2,3-diolato)germanate (3) are easily prepared from GeO2 in quantitative yields. They are very reactive toward organometallic reagents, the reactivity depending on the ligands on the germanium. Complexes 2 react with an excess of Grignard reagent to give the corresponding tetraorganogermanes R4Ge while the less reactive complex 3 leads to the functional triorganogermanes R3GeX. Tetraorganogermanes can also be prepared from complex 2b by reaction with organic bromides in the presence of Mg (Barbier reaction). The influence of Cp2TiCl2 and MgBr2 on the reactivity of Grignard reagents with these complexes was also investigated: in both cases formation of triorganogermanes was favored.
Reactions of nucleophilic reagents with dianionic hexacoordinated germanium complexes: a new convenient route to functional organogermanes from germanium dioxide
作者:G. Cerveau、C. Chuit、R. J. P. Corriu、C. Reye
DOI:10.1021/om00093a038
日期:1988.3
Reaction of vinylgermaniums with butadiene
作者:S. R. Rafikov、I. M. Salimgareeva、N. G. Bogatova、O. Zh. Zhebarov、V. K. Mavrodiev、V. P. Yur'ev