Lead-carbon bonds reactions with

Carbon-carbon bond formation with electrogenerated nickel and palladium complexes in cyclization reactions leading to the formation of heterocycles 03EJ01605. 

PTC was successfully applied to a variety of other carbene reactions such as insertion into CH bonds, reactions with primary and secondary amines (giving isonitriles and A -formylated amines, respectively), Schiff bases (to form dichloroaziridine derivatives), some aromatic heterocycles, carbon-carbon triple bonds and with many other 0,N,S and P nucleophiles. In many cases, these reactions are of practical value only when carried out according to PTC methodology. For instance, the NaOH-promoted reaction of chloroform with primary amines leading to isonitriles (the Hoffman reaction), which are important intermediates in organic synthesis, was previously used only as an analytical method (eqs. 115-118). 

In this reaction, the n bond of the alkene and the C bond of H — Cl have been converted into a pair of C bonds attaching H and Cl to carbon atoms. We must lead into this reaction with a look at the structure and properties of molecules such as hydrogen chloride that contain bonds between two very different kinds of atoms. 

Organometalhcs. Halosilanes undergo substitution reactions with alkali metal organics, Grignard reagents, and alkylaluininums. These reactions lead to carbon—siUcon bond formation. 

Sihcon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. Chemical reactions do, however, take place between sihcon carbide and a variety of compounds at relatively high temperatures. Sodium sihcate attacks SiC above 1300°C, and SiC reacts with calcium and magnesium oxides above 1000°C and with copper oxide at 800°C to form the metal sihcide. Sihcon carbide decomposes in fused alkahes such as potassium chromate or sodium chromate and in fused borax or cryohte, and reacts with carbon dioxide, hydrogen, ak, and steam. Sihcon carbide, resistant to chlorine below 700°C, reacts to form carbon and sihcon tetrachloride at high temperature. SiC dissociates in molten kon and the sihcon reacts with oxides present in the melt, a reaction of use in the metallurgy of kon and steel (qv). The dense, self-bonded type of SiC has good resistance to aluminum up to about 800°C, to bismuth and zinc at 600°C, and to tin up to 400°C a new sihcon nitride-bonded type exhibits improved resistance to cryohte. 

---