Organotin hydride reductions

Organotin Hydride Reductions of (Haloalkyl)cyclopropanes and Related Reactions... 

Table 7. Substituted But-1-enes by Organotin Hydride Reductions of (Haloalkyl)cyclopropanes R R R R ...

Organotin hydride reductions of a variety of polycyclic halides containing three-membered rings have been studied, including the stereoselectivity in the triphenyltin hydride reduction of 6jS-chloro-3,5-cyclocholestanes, Tributyltin hydride reduction of both syn- and anti-1-chloro-2-methylnortricyclene (35) afforded cn fo-5-methylnorbornene (36) as the major product, with very little of the e.w-isomer. ... 

When subjected to organotin hydride reduction mediated by AIBN, an a,y3-... 

Organotin hydride reduction of thionoesters and thionolactones affords the corresponding ethers by hydrosilylation fhen desulfurization (Scheme 12.123) [225]. In this desulfurization process a catalytic amount only of triphenyltin hydride works well use of a stoichiometric amount of expensive organotin hydride is thus avoided. 

H.G. Kuivii.a, Reduction of Organic Compounds by Organotin Hydrides, Synthesis 1970, 499. 

Clive and coworkers have developed a new domino radical cyclization, by making use of a silicon radical as an intermediate to prepare silicon-containing bicyclic or polycyclic compounds such as 3-271 and 3-272 (Scheme 3.69) [109], After formation of the first radical 3-267 from 3-266, a 5-exo-dig cyclization takes place followed by an intramolecular 1,5-transfer of hydrogen from silicon to carbon, providing a silicon-centered radical 3-269 via 3-268. Once formed, this has the option to undergo another cyclization to afford the radical 3-270, which can yield a stable product either by a reductive interception with the present organotin hydride species to obtain compounds of type 3-271. On the other hand, when the terminal alkyne carries a trimethylstannyl group, expulsion of a trimethylstannyl radical takes place to afford vinyl silanes such as 3-272. 

Organotin hydrides R SnI L- , where R represents an alkyl or aryl group, are generally prepared quite easily by reduction of the corresponding organotin halides using either LiAlFLt or NaBFL in ether or dioxane ... 

Several less general methods for preparing organotin hydrides are also used, though often with less satisfactory yields. However, reduction of N, A-diethylaminostannanes by dire -butylaluminum hydride or diborane occurs with high yields224 ... 

As for organogermanium hydrides, a simple organotin hydride, like tri-w-butyltin hydride, can be used for the reduction of structurally more complicated diorganotin dichlorides228 ... 

An application of the reduction method of organotin halides by simple organotin hydrides is the preparation of l, >-bis(hydridodimethylstannyl)alkanes235 ... 

The dehalogenation of organic halides by organotin hydrides takes place in most cases with a free-radical mechanism [1, 84, 85], The stereospecific reduction of 1,1-dibromo-l-alkenes with Bu3SnH discovered by Uenishi and coworkers [86-89], however, did not occur in the absence of palladium complexes and did not involve radicals. For the synthesis of (Z)-l-bromo-l-alkenes, [(PPh3)4Pd] proved to be the most effective catalyst which could also be generated in situ. The reaction in Eq. (7) proceeded at room temperature and a wide range of solvents could be used. 

An analytical procedure for organotin hydrides has been based on the reduction of isatin to oxindole.273... 

It is well known104 that organotin hydrides are very efficient reagents for organic halide reduction. Not surprisingly, therefore, 1-stannaindene (94) in CDCI3 solution gives rise to 1-chloro-l-phenyl-1-stannaindene (95) (equation 38). 

Selective reduction of halides.1 Thecomplexl reduces tertiary halides to alkanes without attack on primary or secondary halides. It is more selective than organotin hydrides. Benzylic and allyl halides are also reduced easily. The reagent reduces a mixture of the halides 2 mainly to trims-3 thus, a partial inversion oftonfiguration is... 

The iodo and bromo derivatives of monosaccharides can be reduced by a variety of reducing agents to afford the corresponding deoxy sugar. Many such examples have been presented. The more stable chloro derivatives can be reduced with Raney nickel (Scheme 1). Selective reduction of a secondary chloride with respect to a primary chloride may be achieved if the reduction is performed in the presence of triethylamine.11,12 Selective reduction of a secondary chloride has been also achieved by using organotin hydrides.13 The radical initiator... 

Dumartin and associates described the preparation of in situ polymer-supported organ-otin hydrides for use as clean reducing agents (equation 15)47, while Deleuze and coworkers reported the preparation of a novel, macroporous polymer-supported organotin hydride (37), for use in catalytic free-radical reductions (equation 16)48,49. 

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