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With tributyl tin hydride

The 4-hydroxyl of 8,9-0-isopropylidene derivative 4b has been protected as its 4-t-butyl-dimethyl-silyl ether 4e. Then, the 7-hydroxyl has been converted to its xantate ester 4f, by deprotonation with butyl litium, treatment with carbon disulfide and alkylation with methyl iodide. Deoxygenatiobn of the 7-position has been accomplished by heating with tributyl-tin hydride in xylenes. Then, the cleavage of acetonide and of silyl ether, by heating in 80% acetic acid, followed by hydrogenolysis to remove the benzyl ester, afford 7-deoxy-Neu%Ac-ctMe Im. [Pg.127]

Alkyl halides can be reduced to alkanes by a radical reaction with tributyl tin hydride, (C4H9)3SnH, in the presence of light (hi ) ... [Pg.383]

Indolyl radicals can be generated under standard conditions by reacting 2-bromoindole with tributyl tin hydride. [Pg.342]

In another approach, Corey, Shibasaki and KnoUe effected a stereospecific Qaisen rearrangement of the unsaturated sugar (107) by reaction with the dimethylaminal of A, A -dimethylacetamide in diglyme, to give the dimethyl-amide (108). The latter then afforded (92b) (a-methoxy epimer) on reaction with iodine and deiodination of the resulting iodolactone with tributyl tin-hydride [92]. [Pg.383]

Tertiary hydroxy groups adjacent to formyl groups in branched-chain sugars can be replaced by hydrogen through free-radical deoxygenation of the benzoate, or preferably the 4-cyanobenzoate, ester with tributyl tin hydride. [Pg.151]

When 1,2,3-selenadiazoles such as 102 are treated with a catalytic amount of tributyl tin hydride and AIBN a vinyl radical species 103 is formed. This radical species can add to electron deficient olefins to give intermediates such as 104 which then undergo intramolecular cyclization to give the dihydroselenophenes such as 105 in moderate to good yields <99TL6293>. [Pg.201]

Tributyl tin hydride [688-73-3] M 291.1, b 76°/0.7mm, 81°/0.9mm, 114 Dissolve in Et20, add quinol (500mg for 300ml), dry over Na2SO4, filter, evaporate and distil under dry N2. It is a clear liquid if dry and decompose very slowly. In the presence of H2O traces of tributyl tin hydroxide are formed in a few days. Store in sealed glass ampoules in small aliquots. It is estimated by reaction with aq NaOH when H2 is liberated. CARE stored samples may be under pressure due to liberated H2. [J Appl Chem 7 366 7957]. [Pg.442]

Treatment of 6 with a benzene solution of tributyl tin hydride 23 and azobis/.vobutyronitrile (AIBN) 22, introduced slowly with a syringe pump at reflux, provided the tricyclic ketone 7 in 82 % yield. Overall only traces of AIBN as radical initiator and not more than a slight excess of Bu3SnH are needed. [Pg.182]

The cyclic (iodomethyl)carbamates 15 can be easily converted into 3-amino-l,2-diol derivatives 17 via iodine displacement with Amberlyst A-26 in the acetate form. In addition, cleavage of the carbon- iodine bond (lithium aluminum hydride or tributyl tin hydride) leads to the trans-2-oxazolidinones 18, which are useful intermediates for the synthesis of 1,2-iyn-amino alcohol systems 199 12. [Pg.257]

The reduction of (3-hydroxyalkyl selenides to alcohols has been achieved - - - by lithium in ethylamine (Scheme 161, a Scheme 162, a Scheme 163, a Scheme 167) or triphenyl- or tributyl-tin hydride in toluene, with or without AIBN. Most of these reactions proceed through radicals. The reactions involving tin hydrides can be carried out thermally around 120 or photochemically at much lower temperature (0-20 The cleavage of the C—SePh bond is faster than that of the... [Pg.699]

The trifluoromethyltin halides, (CF3) SnX4 react with trimethyl- or tributyl-tin hydride at -40 °C to give the trialkyltin halide and the corresponding trifluoromethyltin hydrides (CF3)3SnH, (CF3)2SnH2, CF3SnH3, and (CF3)2SnClH as liquids which are unstable at room temperature.18... [Pg.245]

As will be elaborated upon later in this chapter, glycosyl fluorides and bromides tend to produce a anomeric radicals while chlorides and iodides show substantially less selectivity. One particular study, involving the reduction of glycosyl bromides under various conditions, was reported by Somsak, et al.,8 and is shown in Scheme 5.1.4. As shown, this study compared a variety of reducing conditions on two 1-bromo-l-cyano glycosides. In both cases, utilizing tributyl tin hydride and a radical initiator, the major products observed resulted from delivery of a hydride with retention of the anomeric configurations. These observations support the preferential formation of a anomeric radicals. [Pg.178]

The reaction is usually performed at low temperature, typically 20-50 °C, in order to avoid a reaction of the tin complex with the hydroxy groups of the support, as shown by solid-state C CP-MAS NMR. Indeed, it has been shown that tetra-n butyl tin or tributyl tin hydride reacts, above ca. 150 °C with the hydroxy groups of silica, siUca-alumina or alumina with formation of a surface grafted =M-0-Sn(n- 4119)3 fragment and evolution of butane or hydrogen [61, 109-111] (Scheme 18.5). [Pg.564]

Reduction, which consists of loss of O, gain of H, or gain of electrons by a chemical species, is also a common operation in chemical synthesis. As is the case with oxidants, the reagents used to accomplish reduction can pose hazards and produce undesirable by-products. Such reductants include lithium aluminum hydride, LiAlH4, and tributyl tin hydride. [Pg.373]

A useful synthesis of allylstannanes from primary alcohols involves conversion of the alcohols into their O-substituted 5-methyl carbonodithioates, thermolysis to effect [3,3] rearrangement to the corresponding 5-substituted 5-methyl carbonodithioates, and treatment with a trialkyl-tin hydride under free-radical conditions to form the allylstannane21. This procedure has been applied to the synthesis of functionalized allylstannanes including (5)-( )-4-(benzyloxy)-2-pen-tenyl(tributyl)stannane22. [Pg.360]

Reductions of carbon-halogen bonds are initiated similarly. In this case, several tin hydrides (di- and tributyl, triphenyl) can be used with practically equal effectiveness. lododecane gives the hydrocarbon in 88% yield after sonication for 2 h with triphenyltin hydride in THF at - 64°C. An equivalent yield is obtained using the tributyl analogue in toluene at 6°C. With substrates containing an unsaturation in a suitable position, cyclization occurs (Eq. 9). Interception by oxygen of the intermediate radical can be stopped at the hydroperoxide stage. 4... [Pg.72]

The results of the last two experiments are of great importance. They show clearly that the lead hydrides have a higher reduction potential than the tin hydrides galvinoxyl (21) is not reduced by triethyltin hydride even at 70°-80° C (255), but is reduced by tributyl/ead hydride spontaneously at 0° C. Finally, triethyltzn chloride (22) can be reduced by tributyl/eaJhydride. (Under the same conditions reduction of X.nct y germanium chloride with tributylt/n hydride also takes place spontaneously.)... [Pg.278]


See other pages where With tributyl tin hydride is mentioned: [Pg.73]    [Pg.352]    [Pg.84]    [Pg.130]    [Pg.303]    [Pg.273]    [Pg.54]    [Pg.189]    [Pg.842]    [Pg.73]    [Pg.352]    [Pg.84]    [Pg.130]    [Pg.303]    [Pg.273]    [Pg.54]    [Pg.189]    [Pg.842]    [Pg.10]    [Pg.735]    [Pg.70]    [Pg.177]    [Pg.351]    [Pg.287]    [Pg.136]    [Pg.91]    [Pg.1305]    [Pg.427]    [Pg.214]   
See also in sourсe #XX -- [ Pg.4 , Pg.718 ]




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2.4.5- Tributyl

Tin hydrides

Tributyl tin

Tributyl tin hydride

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