Pyrolysis reductive elimination

Lewis base adducts, 25 64, 68-69 metal exchange reactions, 25 57 NMR spectra, 25 93-95 pyrolysis, 25 107 silicide formation, 25 110 tetracarbonylsilyl hydride reaction with isoprene, 25 75 reductive elimination, 25 81 site, formation, ribonucleotide reductase, 43 372-375... 

Dehydroadamantanes are most readily obtained from either carbene insertion reactions or from 1,3-reductive eliminations. Pyrolysis of the dry sodium salt of the tosylhydrazone of adamantanone gives good yields of 2,4-dehydroada-mantane 133>. The unstable 1,3-dehydroadamantane is obtained from the treatment of 1,3-dibromoadamantane with sodium (Eq. (43)) 134>. 

The platinum(rv) complex [PtlMesCPMeaPh) undergoes a reductive-elimination reaction on pyrolysis ... 

Studies on complexes of the type (10) reveal that no QDe is formed on pyrolysis, and strongly suggest that the reductive elimination is an intramolecular process. It is also apparent from studies on (10) and related complexes that CHg groups are eliminated more readily than CD3 groups and that groups treats to phosphorus are eliminated more readily than the group trans to iodine. 

The general synthetic methods for [2.2] CPs have been already estabhshed. Most of them employ the ring contraction reactions of the 2,11-diheteroatom-substituted [3.3]CPs. Photochemical ehmination of sulfur or selenium atoms from [3.3] CP-2,11-disulfide or diselenide and flash vacuum pyrolysis of sulfur dioxide obtained by the oxidation of the corresponding sulfides are the most general methods. 2,11-Diaza[3.3]CPs are converted to the corresponding [2.2]CPs via their nitroso derivatives by reductive elimination of nitrogen. " Photoextrusion reactions of COj from cychc diesters can also be appHed to the synthesis of [2.2]paracyclophanes (PCPs)"- and [2.2]heterophanes, as described below. "... 

Many other uses of a-sulfinyl carbanions are found in the literature, and in the recent past the trend has been to take advantage of the chirality of the sulfoxide group in asymmetric synthesis. Various ways of preparation of enantiopure sulfoxides have been devised (see Section 2.6.2) the carbanions derived from these compounds were added to carbonyl compounds, nitriles, imines or Michael acceptors to yield, ultimately, with high e.e. values, optically active alcohols, amines, ethers, epoxides, lactones, after elimination at an appropriate stage of the sulfoxide group. Such an elimination could be achieved by pyrolysis, Raney nickel or nickel boride desulfurization, reduction, or displacement of the C-S bond, as in the lactone synthesis reported by Casey [388]. 

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