Tri-n-butyltin

Cyclopentene derivatives with carboxylic acid side-chains can be stereoselectively hydroxy-lated by the iodolactonization procedure (E.J. Corey, 1969, 1970). To the trisubstituted cyclopentene described on p. 210 a large iodine cation is added stereoselectively to the less hindered -side of the 9,10 double bond. Lactone formation occurs on the intermediate iod-onium ion specifically at C-9ot. Later the iodine is reductively removed with tri-n-butyltin hydride. The cyclopentane ring now bears all oxygen and carbon substituents in the right stereochemistry, and the carbon chains can be built starting from the C-8 and C-12 substit""" ... 

Bowmer and Tonelli [161] have also studied the thermal characteristics of the whole range of ethylene-vinyl chloride copolymers prepared by partial reductive dechlorination of PVC using tri-n-butyltin-hydride. Naqvi [162] has substantiated further his explanations for the thermal stability characteristics of ethylene-vinyl chloride copolymers reported by Braun et al. [159] using the results of Bowmer and Tonelli [161] as a basis. 

In an effort to identify a more stereoselective route to dihydroagarofuran (15), trimethylsilylated alkyne 17 was utilized as a substrate for radical cyclization (Scheme 2). Treatment of 17 with a catalytic amount of AIBN and tri-n-butyltin hydride (1.25 equiv) furnishes a mixture of stereoisomeric vinyl silanes 18 (72% combined yield) along with an uncyclized reduction product (13% yield). The production of stereoisomeric vinyl silanes in this cyclization is inconsequential because both are converted to the same alkene 19 upon protodesiiyiation. Finally, a diastereoselective di-imide reduction of the double bond in 19 furnishes dihydroagaro-... 

If the reaction just described is conducted in the presence of a suitable hydrogen atom donor such as tri-n-butyltin hydride or tert-butyl hydrosulfide, reductive decarboxylation occurs via a radical chain mechanism to give an alkane (see 125—>128, Scheme 24). Carboxylic acids can thus be decarboxylated through the intermediacy of their corresponding thiohydroxamate esters in two easily executed steps. In this reducjtive process, one carbon atom, the carbonyl carbon, is smoothly excised... 

Ueno and coworkers10 have found that the facile displacement of sulfonyl group from a-alkylated allyl p-tolyl sulfones 18 by tri-n-butyltin radical in the presence of 2,2 -azobis[2-methylpropanenitrile] (AIBN) occurs smoothly in refluxing benzene (equation 11). In contrast, vinyl sulfones undergo the radical substitution reaction to give vinylstannanes in the presence of AIBN at a higher temperature11. 

Remarkable solvent effects on the selective bond cleavage are observed in the reductive elimination of cis-stilbene episulfone by complex metal hydrides. When diethyl ether or [bis(2-methoxyethyl)]ether is used as the solvent, dibenzyl sulfone is formed along with cis-stilbene. However, no dibenzyl sulfone is produced when cis-stilbene episulfone is treated with lithium aluminum hydride in tetrahydrofuran at room temperature (equation 42). Elimination of phenylsulfonyl group by tri-n-butyltin hydride proceeds by a radical chain mechanism (equations 43 and 44). 

Tri-n-butyltin hydride can also be used for reductive demercuration.20 An alternative reagent for demercuration is sodium amalgam in a protic solvent. Here the evidence is that free radicals are not involved and the mercury is replaced with retention of configuration.21... 

Other reactive forms of nickel including nickel boride283 and nickel alkoxide complexes284 can also be used for desulfurization. Tri-n-butyltin hydride is an alternative reagent for desulfurization.285... 

Starnes and Bovey (1) pioneered the method of I3C NMR analysis of reduced poly(vinyl chloride) (PVC) to study the microstructure of PVC. Tri-n-butyltin hydride ((n-Bu)3SnH) was found to completely dechlorinate PVC resulting in polyethylene (PE) whose microstructure (branching, end-groups, etc.) could be sensitively studied by 13C NMR. 

A copolymer of tri-n-butyltin methacrylate (TBTM) and methyl methacrylate (MMA), which is the active agent in antifouling... 

Atactic poly(methyl methacrylate/methacrylic acid), the copolymer of methyl methacrylate (MMA) and methacrylic acid (MAA), was synthesized "directly" as a prepolymer to be esterified with bis(tri-n-butyltin) oxide (TBTO). Two formulations of poly (MMA/MAA) were synthesized, a 1 1 and a 2 1 MMA and MAA copolymer whose syntheses differ only in the proportion of monomer reacted. 

In a second method, a 1 g sample of poly(tri-n-butyltin methacrylate/methyl methacrylate) was dissolved in 4 mL of chloroform. One mL of concentrated HC1 was added dropwise with shaking until no more precipitate appeared. The precipitate was removed and then shaken again with a clean batch of chloroform and HC1. 

Tri-n-butyltin methacrylate (TBTM) was synthesized by chemists at the David Taylor Naval Ship Research and Development Center (DTNSRDC), Annapolis, Maryland. The methods of Dyckman et al. (1 ) and Montermoso et al. (2 ) were used, in which 30 g methacrylic acid was slowly added to 103.8 g bis(tri-n-butyltin) oxide in 300 mL benzene in a flask equipped with a stirrer and reflux condenser. Cooling kept the temperature below 25°C. After all acid had been added, the solution was heated gradually and maintained at 30°C while the water of reaction was removed in vacuo and benzene was added to replace the benzene lost during this period. When the solution became clear, the benzene was removed and the resulting pale yellow viscous liquid was diluted with 100 mL ether and cooled to -20°C. The product separated as long, thick, transparent needles. The yield was close to theoretical and the ra.p. was 18°C. 

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