Methyl stannyl

Bis(triphenyltin)dihydridobis(methyldiphenylphosphine)plati-num, see Sn-00474 Bis(triphenyltin)oxide, see Sn-00440 >Bis(triphenyltin) sulfide, Sn-00443 Bis(triphenyltin)telluride, Sn-00446 >Bis(tripropyltin) oxide, see Sn-00339 >Bis[tris(2-methyl-2-phenylpropyl)tin] oxide, see Sn-00473 Bis[tris(pentafluorophenyl)germyl]cadmium, Ge-00271 Bis[tris(pentafluorophenyl)germyl] mercury, Ge-00273 Bis[tris(pentafluorophenyl)germyl] selenide, see Ge-00275 Bis[tris(pentafluorophenyl)germyl] sulfide, see Ge-00274 [Bis[tris(pentafluorophenyl)stannyl]]mercury, Sn-00435 Bis[tris(trifluoromethyl)germanium]oxide, see Ge-00064 Bis[tris[(trimethylsilyl)methyl]stannyl]mercury, Sn-00399 Bromo( 7 -2,4-cyclopentadien-1 -yl)lead, Pb-00035 Bromo( 7 -2,4-cyclopentadien-1 -yl)tin, Sn-00086 Bromodimethylstannane, Sn-00022... 

Bis[tris[(trimethylsilyl)methyl]stannyl]mereury, Sn-00399 1 25H2oFeGe02... 

Diethyl(trimethylgermyl)phosphine, Ge-00096 34478-38-1 Tetrakis(trimethylgermyl)hydrazine, Ge-00170 34478-39-2 Tetrakis(trimethylstannyl)hydrazine, Sn-00271 34501-62-7 Bis[tris[(trimethylsilyl)methyl]stannyl]mercury, Sn-00399... 

Chloro(trimethylplumbyl)magnesium, Pb-00013 51275-77-5 Tris[bis(trimethylsilyl)methyl]stannyl, Sn-00364... 

Photonucleophilic aromatic substitution reactions of phenyl selenide and telluride with haloarenes have also been proven to involve the S jlAr mechanism, with the formation of anion radical intermediates. Another photonucleophihc substitution, cyanomethylation, proves the presence of radical cations in the reaction mechanism. Liu and Weiss have reported that hydroxy and cyano substitution competes with photo substitution of fluorinated anisoles in aqueous solutions, where cation and anion radical intermediates have been shown to be the key factors for the nucleophilic substitution type. Rossi et al. have proposed the S j lAr mechanism for photonucleophihc substitution of carbanions and naphthox-ides to halo anisoles and l-iodonaphthalene. > An anion radical intermediate photonucleophilic substitution mechanism has been shown for the reactions of triphenyl(methyl)stannyl anion with halo arenes in liquid ammonia. Trimethylstannyl anion has been found to be more reactive than triphenylstannyl anion in the photostimulated electron- transfer initiation step. 

Methyl-2-(tri-n-butyl-stannyl)indole 4-Bromobenzonitrile, Pd(PPh3),Cl, 91 [2]... 

Several catalytic systems have been reported for the enantioselective Simmons Smith cyclopropanation reaction and, among these, only a few could be used in catalytic amounts. Chiral bis(sulfonamides) derived from cyclo-hexanediamine have been successfully employed as promoters of the enantioselective Simmons-Smith cyclopropanation of a series of allylic alcohols. Excellent results in terms of both yield and stereoselectivity were obtained even with disubstituted allylic alcohols, as shown in Scheme 6.20. Moreover, this methodology could be applied to the cyclopropanation of stannyl and silyl-substituted allylic alcohols, providing an entry to the enantioselective route to stannyl- and silyl-substituted cyclopropanes of potential synthetic intermediates. On the other hand, it must be noted that the presence of a methyl substituent at the 2-position of the allylic alcohol was not well tolerated and led to slow reactions and poor enantioselectivities (ee<50% ee). ... 

Polar functional groups such as carbonyl, cyano, and sulfoxide, as well as silyl and stannyl groups, exert a strong directing effect, favoring proton removal from the geminal methyl group.171... 

Trialkyl (triaryl)stannyl methacrylates were copolymerized with ethylene and methyl methacrylate and it was shown that the resulting copolymer offers improved mechanical properties as compared to ethylene, and high fungicidal activity. It was suggested that homopolymers and copolymers of triethylstannyl methacrylate contain a covalent and an ionic bond between the carboxy group and the tin atom 63). 

The stannyl hydride 30, in contrast, showed nonequivalence of the geminal methyls for the neat sample up to 222 °C. Furthermore, no noticeable line broadening was observed in DMSO-dioxane at 160 °C. Thus, it may be concluded that the hydride 30 is configurationally stable while the chloride 29 is not. 

The configurational stability of triorganotin halides is considerably enhanced by the presence of an amine ligand that can coordinate intramolecularly with the tin atom. This was demonstrated by analysis of the 111 NMR spectrum of the stannyl bromide 47 depicted in Figure 626. Below 30 °C, both theN-methyl and the benzylic protons are diastereotopic ... 

An alternative synthesis of nonracemic a-amino stannanes is outlined in equation 3777. The diastereomeric stannanes, obtained by sequential lithiation and stannylation of the starting nonracemic piperidinooxazoline, can be separated by chromatography. Subsequent removal of the chiral auxiliary and N-methylation completes the synthesis. 

Dipolar cycloaddition reaction of trimethylstannylacetylene with nitrile oxides yielded 3-substituted 5-(trimethylstannyl)isoxazoles 221. Similar reactions of (trimethylstannyl)phenylacetylene, l-(trimethylstannyl)-l-hexyne, and bis (trimethylsilyl)acetylene give the corresponding 3,5-disubstituted 4-(trimethyl-stannyl)isoxazoles 222, almost regioselectively (379). The 1,3-dipolar cycloaddition reaction of bis(tributylstannyl)acetylene with acetonitrile oxide, followed by treatment with aqueous ammonia in ethanol in a sealed tube, gives 3-methyl-4-(tributylstannyl)isoxazole 223. The palladium catalyzed cross coupling reaction of... 

A versatile activating group for the removal of a-protons that are not benzylic is the carbamate fert-butoxycarbonyl, or t-Boc group, developed for this purpose by Beak and Lee in 1989. Its utility derives from the fact that the Boc group is easy to attach to a secondary amine, and easy to remove after a deprotonation/alkylation sequence. Moreover, stannylation affords a-amino-organostannanes that are themselves useful precursors of a-amino-organolithium compounds (Scheme 29) (see Section II). In a chiral pyrrolidine system, it has been shown that both deprotonation (H Li) and methylation (Li Me) occur with retention of configuration. 

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