Tin—boron bonds

The relatively high stability of carbon-silicon/-boron/-tin bonds allows the metaT to be carried through many heterocyclic syntheses as an inert substitutent some examples are shown below. ... 

Tin-boron bonds have been formed by the metathesis of triethyltin lithium with the respective dimethylaminoboron chlorides to give species containing either one or two boron-tin bonds, as illustrated in Fig. 24 (c) and (d)2S7. 

Positively charged or neutral electron-deficient groups may serve as interaction sites for anion binding. Ammonium and guanidinium units, which form +N-H" X bonds, have mainly been used, but neutral polar hydrogen bonds (e.g., with -NHCO- or -COOH functions), electron-deficient centers (boron, tin, mercury, [3.6, 3.7] as well as perfluoro crown ethers and cryptands [3.8], etc.), or metal-ion centres in complexes also interact with anions. 

Vinylsilanes react with boron trichloride to give the corresponding borodesilylation products in good yield which, in turn, can be transformed into boronic esters 124 by alcoholysis (equation 102). The initial dichloroorganoborane products can be used directly in the Suzuki-Miyaura cross-coupling reaction192. Replacement of a carbon-silicon bond by a carbon-tin bond in fluorinated alkenes (e.g. 125) can be achieved by the reaction of silanes with Bu3SnCl and KF in DMF under mild conditions (equation 103)193. It is... 

Element-element bonds, addition to G-G multiple bonds arsenic—selenium bonds, 10, 782 boron—boron bonds, 10, 727 boron—sulfur bonds, 10, 778 B-S and B-Ge bonds, 10, 758 chalcogen—chalcogen additions, 10, 752 germanium—germanium bonds, 10, 747 germanium-tin bonds, 10, 780 overview, 10, 725-787 phosphorus—phosphorus bonds, 10, 751 phosphorus—selenium bonds, 10, 782 phosphorus-sulfur bonds, 10, 781 Se-Si and Se-Ge bonds, 10, 779 silicon-germanium bonds, 10, 770 silicon-phosphorus bonds, 10, 780 silicon-silicon bonds, 10, 734 silicon-sulfur bonds, 10, 779 silicon-tin bonds, 10, 770 tin-boron bonds, 10, 767 tin-tin bonds, 10, 748... 

Homonuclear carbonyl dimers, palladium complexes, 8, 206 Homonuclear element-element bonds, addition to C-C multiple bonds boron-boron bonds, 10, 727 chalcogen-chalcogen additions, 10, 752 germanium-germanium bonds, 10, 747 phosphorus-phosphorus bonds, 10, 751 silicon—silicon bonds, 10, 734 tin—tin bonds, 10, 748... 

C-C bonds. It needs only to be emphasized that, in addition to the silyl enol ethers shown in the scheme, modem organic synthesis extensively employs enolates of boron, tin, titanium, zirconium, and other elements, as their utilization offers additional opportunities to achieve higher efficiency and exert control over the selectivity of the corresponding reactions. 

Vinyllead and alkynyllead tricarboxylates can only be prepared by metal-metal exchange, such as mercury-lead,ll6 ll7 tin-lead,ll6,ll7 boron-lead i or zinc-lead.l In the case of tin-lead exchange, cleavage of the methyl-tin bond is much slower than cleavage of the vinyl-tin or alkynyl-tin bond. Therefore (trimethyl)vinyltin derivatives are preferred to the corresponding (tributyl)vinyltin analogues for the synthesis of the unstable vinyllead and alkynyllead compounds. 

Cleavage of the boron—Co bond by tin halides yields Sn—boron bonds . The route supplements those involving stannyl-alkali-metal reagents and haloaminoboranes ( 5.3.17.2.2). 

The complexes 10.8, 10.9 and ds-(Ph3P)2Pt(EMe3)[B(NzPr)2C6H4-l,2] (10.10) have been synthesized by Noth and Habereder via the oxidative addition of boron-tin or boron-germanium bonds to Pt(0) precursors [217]. 

The organotin derivative (7) was prepared from D-mannose, and some reactions involving Sn-Li exchange were studied, while the relative reactivities of some C-triphenylstaimyl-carbohydrate derivatives in iodine-induced phenyl-tin bond cleavage reactions have been determined. Nucleophilic addition of a carbanionic carborane to a number of sugar aldehydes has provided adducts that were used in attempts to increase the water solubility of carborane - antibody complexes with a view to localising boron on tumors prior to... 

Fig. 24. Some examples of metal-metal bonded species containing (a) cadmium-tin bonds, (b) zinc-tin bonds, (c) and (d) tin-boron bonds.

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