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Preparation and characterization of solution generated lithium stannide mixtures and their chemical applications
The preparation and characterization of solution generated lithium stannide mixtures and their chemical applications are described. Lithium stannide mixtures were prepared from an excess of lithium naphthalenide and tin (II) chloride at room temperature. Several analysis methods such as elemental analysis, X-ray diffraction, and solid state 7Li-NMR were performed to characterize lithium stannide mixtures. The solution generated lithium stannide mixtures were composed of Sn (0), LiSn2, LiSn, and Li5Sn 2. Lithium stannide mixtures successfully performed the reductive cleavage of carbon-halogen bonds in aryl halide substrates. Diethylamine was required for the reductive cleavage of electron withdrawing groups, such as ester and nitrile, substituted aryl halides. ^ Lithium stannide mixtures were also used to initiate Li-Barbier reactions with aldehydes and ketones at room temperature with moderate to good yields. In particular, C(sp2)-C(sp2) coupling reactions between aryl halides and symmetric ketones were carried out. Alkenes could be easily obtained from simple acid catalyzed hydrolysis of the tertiary alcohol products formed in Li-Barbier reactions. ^ Functionalized Grignard reagents were prepared at low temperature (−78°C) by direct oxidative addition of active magnesium (Mg*) with functionalized aryl bromides and iodides. Functional groups such as ester, nitrile, and chloride were tolerated during the oxidative addition and subsequent reaction with aldehyde, acid chloride, or allyl iodide electrophiles. ^ Functionalized bibenzyl compounds were prepared from the homocoupling reactions of functionalized benzyl bromides with active manganese (Mn*) at room temperature within 10 minutes, and in the absence of any additional catalyst. ^
Lee, Junsik, "Preparation and characterization of solution generated lithium stannide mixtures and their chemical applications" (2003). ETD collection for University of Nebraska - Lincoln. AAI3092567.