15784-22-2Relevant academic research and scientific papers
Stereospecific formation of optically active trialkylsilyllithiums and their configurational stability
Omote, Masakatsu,Tokita, Tetsushi,Shimizu, Yasutaka,Imae, Ichiro,Shirakawa, Eiji,Kawakami, Yusuke
, p. 20 - 25 (2007/10/03)
Optically active trialkylsilyllithiums, (R)-(n-butyl)methylphenylsilyllithium (63% ee) and (S)-methyl(1-naphthyl)phenylsilyllithium (96% ee), were prepared by cleavage of the silicon-silicon bond of (R)-1-(n-butyl)-1 -methyl-1-phenyl-2,2-diphenyl-2-methyl
NUCLEOPHYLIC SUBSTITUTIONS AT SILICON; EVIDENCE FOR ION-PAIR DISSOCIATION AS CONTROLLING FACTOR OF THE STEREOCHEMISTRY AND A SIMPLE MECHANISTIC PROPOSAL
Corriu, R. J. P.,Guerin, C.
, p. 2467 - 2472 (2007/10/02)
Stereochemical and kinetic data are reported for reactions between organolithiums or LiAlH4 and some chiral organosilanes.They rule out a mechanism involving complexation control, such as the SNi-Si process proposed by Sommer et al.Electrophylic assistance to cleavage of a Si-X bond does not control the stereochemistry, but acts as an additional factor which can facilitate the inversion by increasing the ability of the leaving group to depart.The results reveal the dominant influence of ion-pair dissociation, and thus of the electronic character of the nucleophile: the consequence of the use of either hard reagents with a localized negative charge, such as alkyllithiums, or softer reagents with a more delocalized negative charge, support this dependence.A simple mechanistic interpretation of the data is proposed, based on a description of nuclepohilic substitutions at silicon as a frontier orbital process.
