459799-25-8Relevant academic research and scientific papers
A Convergent Method for the Synthesis of Highly Enantiomerically Enriched Cyclic Silanes with Silicon-Centered Chirality
Oestreich, Martin,Schmid, Ulrike K.,Auer, Gertrud,Keller, Manfred
, p. 2725 - 2739 (2007/10/03)
A preparatively straightforward methodology has been developed which allows the assembly of silicon-containing carbocycles as mixtures of diastereomers with silicon as the sole center of stereogenic information. One-step construction of the chiral cyclic silanes is realized by reaction of equimolar amounts of a dibromide and a chirally modified dichlorosilane under Barbier conditions giving access to several monofunctionalized 1-sila-1,2,3,4-tetrahydronaphthalenes and a corresponding phenanthrene derivative. Facile large scale syntheses of 3-(2-bromoaryl)propyl bromides as well as dichlorosilanes have been elaborated. This highly convergent methodology relies on the novel (-)-menthyloxy-substituted dichlorosilanes, which have the chiral auxiliary for the subsequent optical resolution installed. These enantiopure dichlorosilanes are useful building blocks for a general and modular one-step approach to silanes with silicon-centered chirality since this strategy avoids the linear sequences reported in literature. The optical resolution has been exemplarily optimized for the 1-phenyl-1-sila-1,2,3,4- tetrahydronaphthalene derivative and the absolute configuration has been established by X-ray crystallography. The chiral auxiliary is stereospecifically displaced by simple reduction providing the highly enantioenriched silane (er = 98:2) which is enantiospecifically chlorinated as verified by a Walden inversion at silicon.
Cyclic chiral silyl derivatives for the determination of the absolute configuration of aliphatic diols by gas chromatography
Arsene, Cristian,Schulz, Stefan
, p. 2869 - 2871 (2007/10/03)
(figure presented) Chiral bidentate silyl reagents have been developed for the GC analysis of aliphatic 1,3-and 1,4-diols. These reagents react with the diols to cyclic siloxanes, which allow the determination of their enantiomeric composition even in complex mixtures. The absolute configuration of 4,6-nonadecanediol 7, occurring in the lipids of sunflower pollen, has been determined to be (4S,6R) by comparison with derivatized synthetic enantiomers.
