Tributylstannane

The reaction of the 1- and (2-ethoxyvinyl)tributylstannanes (721) and (723) as masked carbonyls with aryl halides proceeds smoothly and the products 722 and 724 are used for further reactions[592,593]. 

The alkynyl ketones 840 can be prepared by the reaction of acyi chlorides with terminal alkynes, Cul in the presence of Et3N is the cocatalyst[719]. (1-Alkynyl)tributylstannanes are also used for the alkynyl ketone synthesis[720]. The a,. 3-alkynic dithio and thiono esters 842 can be prepared by the reaction of the corresponding acid chloride 841 with terminal alkynes[721,722]. 

The o -diketone 865 can be prepared by the coupling of the acylstannane 864 with acyl chlorides[738,739]. The a-keto ester 868 is prepared by the coupling of (a-methoxyvinyl)tributylstannane (866) with acyl chloride, followed by ozo-nization of the coupled product 867[740,741],... 

Pd(Ph3P)4, 2-ethylhexanoic acid or barbituric acid (THF, 3 h, 93% yield). Tributylstannane can serve as an allyl scavenger. ... 

Addition reactions of various a-alkoxy lithium and a-alkoxy magnesium compounds 13, formed via the corresponding tributylstannanes, have been performed8. In every case the... 

In order to test whether this high level of diastereoselectivity is due to the stereoselective formation of 35 A, or a consequence of rapid equilibration between 35 A and 35 B, both reagents were selectively prepared via the tributylstannanes 38. Treatment of either reagent with chloro-trimethylsilane led to a similar ratio of the diastereomers 36 A/36B, with the anti-diastereomer 36A predominant in both reactions. 

R)-l-(benzyloxyrnethoxy)-3-substituted-2-propenyl]tributylstannanes yield 64% 60% ee106 8 [ S)-l-(benzyloxymethoxy)-3-substituted-2-propeny ]tributyktannanes105106 yield 65% > 95% ee... 

Treatment of a-sulfonyl carbanion with (iodomethyl)trimethylsilane gave / -trimethylsilyl sulfones289-291. Alkylation of / -trimethylsilyl sulfones 235 gave various /Mrimethylsilyl sulfones292. The use of (iodomethyl)tributylstannane instead of (iodomethyl)trimethylsilane was shown to afford a tributylstannanyl derivative293. This compound has been used for syntheses of terminal olefins289-293. 

A related convenient and mild method for the preparation of aliphatic and aromatic aldehydes in high yield from carboxylic acids is the reductive cleavage of l-acyl-3-methylimidazole-2-thiones by tributylstannane. 

Imidazole-A-thionocarboxylates (also called thiocarbonylimidazolides ) are intermediates in a convenient radical-induced deoxygenation of primary and secondary alcohols with tributylstannane (Barton reaction).[1],[2]... 

Martin and coworkers [93] described a highly efficient enantioselective total synthesis ofmanzamine A (6/1-177) with a concise domino Stille/Diels-Alder reaction to construct the tricyclic ABC ring core in 6/1-177 as the key step. Reaction of 6/1-178 with vinyl tributylstannane in the presence of (Ph3P)4Pd afforded the triene... 

In order to establish the correct absolute stereochemistry in cyclopentanoid 123 (Scheme 10.11), a chirality transfer strategy was employed with aldehyde 117, obtained from (S)-(-)-limonene (Scheme 10.11). A modified procedure for the conversion of (S)-(-)-limonene to cyclopentene 117 (58 % from limonene) was used [58], and aldehyde 117 was reduced with diisobutylaluminium hydride (DIBAL) (quant.) and alkylated to provide tributylstannane ether 118. This compound underwent a Still-Wittig rearrangement upon treatment with n-butyl lithium (n-BuLi) to yield 119 (75 %, two steps) [59]. The extent to which the chirality transfer was successful was deemed quantitative on the basis of conversion of alcohol 119 to its (+)-(9-methyI mande I ic acid ester and subsequent analysis of optical purity. The ozonolysis (70 %) of 119, protection of the free alcohol as the silyl ether (85 %), and reduction of the ketone with DIBAL (quant.) gave alcohol 120. Elimination of the alcohol in 120 with phosphorus oxychloride-pyridine... 

Representative procedure for the synthesis of (Z)-a-selenenylvinylstannanes [34] A mixture of Cp2Zr(H)Cl (1.1 mmol) and (3-methoxy-l-propynyl)tributylstannane (1.0 mmol) in THF (5 mL) was stirred at room temperature for 20 min. A solution of PhSeBr (1.0 mmol) in THF (4 mL) (prepared in situ) was then injected into the resulting solution and the mixture was stirred at room temperature for 30 min. It was then diluted with light petroleum and stirred for a further 5 min., after which the supernatant was filtered through a short plug of silica gel. After evaporation of the solvent from the filtrate, the residue was purified by preparative TLC on silica gel to yield (lZ)-tributyl-[3-methoxy-l-(phenylse-leno) -1 -propenyl] stannane (60 %). 

The indolyltributylstannanes, which are more robust than their trimethylstannyl counterparts, are prepared similarly [166, 167]. Labadie and Teng synthesized the IV-Me, N-Boc, and jV-SEM (indol-2-yl)tributylstannanes [167], and Beak prepared the A-Boc trimethyl- and tributyltin derivatives in high yield [166]. Caddick and Joshi found that tributylstannyl radical reacts with 2-tosylindoles to give the corresponding indole tin compounds as illustrated [168]. 

The review is divided into sections according to the type of metal hydride for convenience in discussing the information systematically. At one extreme, kinetic studies have been performed with many types of silicon hydrides, and much of the data can be interpreted in terms of the electronic properties of the silanes imparted by substituents. At the other extreme, kinetic studies of tin hydrides are limited to a few stannanes, but the rate constants of reactions of a wide range of radical types with the archetypal tin hydride, tributylstannane, are available. Kinetic isotope effects for the various hydrides are collected in a short section, and this is followed by a section that compares the kinetics of reactions of silicon, germanium, and tin hydrides. 

With good hydrogen donors photoreduction of nitrobenzene becomes more efficient the rate constant for hydrogen abstraction from tributylstannane by (n, 7i )-nitrobenzene has been determined as 4 x 10 1 mole s-i... 

Upon irradiation (366 nm) in 2-propanol, 1-nitronaphthalene is inefficiently photoreduced (Ah<10 1 moles i s i) despite its high triplet yield 3). With tributylstannane, a marked increase of the hydrogen abstraction rate (<3 x 10 ... 

Lithium tetrahydroaluminate Lithium tetrahydridoaluminate Sodium tetrahydroborate Sodium tetrahydridoborate Lithium trialkoxyhydridoaluminate Sodium bis(2-methoxyethoxy)dihydro-aluminate Diisobutylalane Tributylstannane... 

Geminal dihalides undergo partial or total reduction. The latter can be achieved by catalytic hydrogenation over platinum oxide [512], palladium [512] or Raney nickel [63, 512], Both partial and total reduction can be accomplished with lithium aluminum hydride [513], with sodium bis(2-meth-oxyethoxy)aluminum hydride [514], with tributylstannane [503, 514], electro-lytically [515], with sodium in alcohol [516] and with chromous sulfate [193, 197]. For partial reduction only, sodium arsenite [220] or sodium sulfite [254] are used. 

Chemical reduction of aromatic aldehydes to alcohols was accomplished with lithium aluminum hydride [5i], alane [770], lithium borohydride [750], sodium borohydride [757], sodium trimethoxyborohydride [99], tetrabutylam-monium borohydride [777], tetrabutylammonium cyanoborohydride [757], B-3-pinanyl-9-borabicyclo[3.3.1]nonane [709], tributylstannane [756], diphenylstan-nane [114], sodium dithionite [262], isopropyl alcohol [755], formaldehyde (crossed Cannizzaro reaction) [i7i] and others. 

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