Germyls

Indazole, 5,5-dimethyl-3-trifluoromethyl-4,5-dihydro-trichomonacidal activity, 5, 291 Indazole, 2-ethoxycarbonyl-reactions, 5, 269 Indazole, 3-fluoro-synthesis, S, 263 Indazole, 1-germyl-synthesis, 5, 236 Indazole, 1-glycosyl-synthesis, 5, 289 Indazole, 2-glycosyl-synthesis, 5, 289 Indazole, halo-reactions, S, 266 Indazole, 2-hydroxy-methylation, 5, 269 Indazole, 3-hydroxy-reactions, S, 264 Indazole, 6-hydroxy-diazo coupling, 5, 86 Indazole, hydroxyphenyl-synthesis, S, 288 Indazole, 3-iodo-synthesis, S, 241 Indazole, l-isopropyl-3-phenyl-reduction, 5, 243 Indazole, 3-mercapto-1 -substituted tautomerism, 5, 265 Indazole, methoxy-... 

Pyrazole, C-formyl-conformation, 5, 209 Pyrazole, fluoro-reactions, 5, 263, 267 Pyrazole, 4-fluoro-5-hydroxy-tautomerism, 5, 214 Pyrazole, 1-germyl-synthesis, 5, 236 Pyrazole, halo-halogenation by, 5, 54 reactions, 5, 104, 105, 266 reduction, S, 105, 106, 266 Pyrazole, 3-halo-1-phenyl-quaternary salts... 

The H and 13C CIDNP studies have shown that not only the sulfone 14, but also the sulfmic ester 15, is generated as cage products from the phenyl/p-toluenesulfonyl radical pair during the thermal decomposition of phenylazo aryl sulfone (13)54 (Scheme 2). The cross-termination of arenesulfonyl and triethylgermyl radicals was found to occur exclusively via the formation of germyl sulfinate, ArS(0)0GeEt333. 

C. H. van Dyke Prep. Inorg. React. Inorganic derivatives of germane 76 Pp. 215-218 germyl-transition... 

In the field of germyl cations, several remarkable examples were recently reported. Thus, the transient germyl cation, prepared as shown in Scheme 2.5, B (Section... 

The development of sophisticated new experimental techniques during the last decade has made possible the isolation of stable representatives of the free radical species featuring an nnpaired electron on the heavier group 14 elements, that is, silyl, germyl, and stannyl radicals. This great progress in the isolation of the stable radicals opens unprecedented possibilities for their structural characterization in the crystalline form, which in tnrn enables the direct comparison of the fundamental differences and similarities between the solntion and solid state strnctnres of the free radical species. " ... 

Germyl, Stannyl, and Plumbyl Anions The preparative methods for the synthesis of the germyl, stannyl, and plumbyl anions are essentially the same as those mentioned above for the silyl anions. The most widely used methods are (1) reduction of halides R3EX (R = alkyl, aryl E = Ge, Sn, Pb X = Cl, Br) with alkali metals and (2) reductive cleavage of the E-E bond of R3E-ER3 (R = alkyl, aryl E = Ge, Sn, Pb) with alkali metals or organolithium reagents. Due to the favorable polarization of the (E = Ge, Sn, Pb) bond, the direct metalation... 

An interesting bicyclic germyl anion 42 K was readily prepared by the reduction of bicyclic iodide 78 with KCg (Scheme 2.71). The Ge anionic center in 42 [K (dme)2] was highly pyramidalized with the normal value of the Ge-K bond distance (3.4324(10) A). However, in polar solvents (THF) the Ge-K bond dissociates to produce 42 as an SSIP featuring the free anion 42 . 

The first solution ESR spectra of the transient radicals were observed in 1969 and 1972. Silyl radicals see refs. 121a,c. Germyl radicals see ref 121a. Stannyl radicals ref. 97. 

In order to overcome the difficulties of thermal instability, the phosphasilene derivatives 15, which bear a silyl or germyl group attached to phosphorus, were synthesized. Indeed, they proved to have stronger Si=P bonds (stable up to 100°C), thus allowing studies of their structures and reactivity.l0b 14 Phosphasilenes 15a-15i were synthesized from the corresponding Iithium(fluorosilyl)phosphanides 16a-16i by the thermally induced elimination of LiF (see Scheme 4).10b It has been shown that excellent steric protection of the highly reactive Si=P bond in 15 is provided by the 2,4,6-triisopropylphenyl (Is = isityl) substituent attached to the low-coordinate silicon center. The appropriate precursors 16a-16i were synthesized in a multiple-step procedure, starting from 17 (Scheme 4).10b U... 

On silylation/germylation of 17, compounds 18 were formed, which were subsequently lithiated on phosphorus to yield 16. It appears that the success of the next step from 16 to 15 depends on different factors, but the following three parameters may be regarded as critical (1) The reaction temperature for the elimination of LiF should not exceed 80°C (2) the concentration of 16 dissolved in hexane or toluene should be about <0.1 mol L (3) the steric bulk and electronic influence of the substituent attached to phosphorus should be optimized. In the first place, the nature of the substituent at phosphorus determines the structures of the precursors 16. This has been demonstrated by a study of a structure-reactivity... 

Especially noteworthy is the relative large shielding for the 31P nucleus in the 31P NMR spectra of 15, which is quite unusual for two-coordinate phosphorus. Evidently, the latter is caused by the strong o--donor ability of the silyl and germyl groups, which is also reflected in the calcu-... 

The addition of bromine or iodine to Mes2Ge=PAr (Ar = 2,4,6-tri-/-butylphenyl) gave two major products the vicinal dihalide and the (halo-germyl)phosphine.59... 

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