- Selective Preparation of Sterically Encumbered Diaryltin Dihalides from Grignard Reagents via Salt Metathesis and Halide Exchange
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A general route for the selective preparation of diaryltin dichlorides, dibromides, and diiodides from readily accessible but sterically demanding, 2,6-disubstituted or 2,4,6-trisubstituted aryl Grignard reagents ArylMgBr and tin tetrachloride was developed. During work-up, the initially obtained mixture of halides is converted into a single species. The thus obtained diaryltin dichlorides were reacted to yield the dihydrides Aryl2SnH2. These exhibit high thermal stability and moderate oxygen tolerance.
- Steller, Beate G.,Fischer, Roland C.
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p. 2591 - 2597
(2019/06/14)
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- The allyl leaving group approach to tricoordinate silyl, germyl, and stannyl cations
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A group 14 atom bonded to three mesityl groups (2,4,6-trimethylphenyl) and to one allyl group serves as a novel precursor to tricoordinate group 14 cations, the analogues of the carbocation. The double bond of the allyl group provides an accessible reaction site that is located beyond the ortho methyl groups. Reaction of various electrophiles with the double bond releases the allyl group and leads to formation of the group 14 cations. The mesityl groups then are of sufficient steric bulk to protect the tricoordinate metal center from attack by nucleophiles. This approach is used herein with silicon, germanium, and tin as the central atom. The 29Si chemical shift (δ 225) indicates full cationic character for the silicon system. The 119Sn chemical shift (δ 806) indicates less than full cationic character for the tin system. The positive charge for the germanium system has been assessed by examination of the aromatic 13C chemical shifts. These results provide the highest current cationic character for silylium and stannylium ions.
- Lambert, Joseph B.,Zhao, Yan,Wu, Hongwei,Tse, Winston C.,Kuhlmann, Barbara
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p. 5001 - 5008
(2007/10/03)
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