Alkanes Tributyltin hydride

Alkyl halides can be reduced to alkanes by a radical reaction with tributyltin hydride, (C4H9)3SnH, in the presence of light (hv). Propose a radical chain mechanism by which the reaction might occur. The initiation step is the light-induced homolytic cleavage of the Sn— H bond to yield a tributyltin radical. 

The 3-butenylphenyl radical can either react with tributyltin hydride to form an alkane or undergo a ring closure to form cyclic products (Scheme 28). 

Sodium triacetoxyborohydride, 283 Titanium(III) chloride, 302 Tributyltin hydride, 316 Zinc borohydride, 167 of alkenes to alkanes (R)-(-F)- and (S)-(-)-2,2 -Bis(di-phenylphosphine)-l,1 -binaphthyl, 36 [1,4-Bis(diphenylphosphine)-butanej(cycloheptatriene)-rhodium(I) tetrafluoroborate, 89 [ 1,4-Bis(diphenylphosphine)butane]-(norbornadiene)rhodium(I) tetrafluoroborate, 37... 

The radical decarboxylation of a Barton ester proceeds to the corresponding alkane after treatment with tributyltin hydride or t-butylmercaptan ... 

Decarboxylation of the aliphatic esters of A-hydroxypyridine-2-thione by tributyltin hydride leads to reduction of the radical and the formation of the alkane lacking the carboxyl carbon, as in the Barton-McCombie reaction (Scheme 3.61). 

In the presence of a radical initiator (Z-), tributyltin hydride (RgSnH, R = CH3CH2CH2CH2) reduces alkyl halides to alkanes R X + RgSnH -> R H + RgSnX. The mechanism consists of a radical chain process with an intermediate tin radical ... 

Alkyl halides can be reduced to alkanes by a radical reaction with tributyltin hydride, (C HalsSnH, in the presence of light (kif) ... 

The reaction of selenol esters with tributyltin hydride resulted in the formation of the corresponding aldehydes (49) and alkanes (50). The formation ratio of aldehydes to alkanes depends on Ae reaction temperature, as exemplified in Scheme 15. When the reaction was carried out with UV irradiation at ambient temperature, the aldehyde was formed predominantly, in high yields. 

Bicyclo[n.l.O]alkan-l-oxyl radicals are fleeting intermediates in homolytic reactions of 2-(halomethyl)cycloalkanones and related radical precursors. Unrearranged 2-methyl-cyclohexanone (19) was obtained from treatment of 2-[(phenylselanyl)methyl]cyclohexanone (18) with tributyltin hydride. ... 

Reductions of 2-halobicyclo-[n. 1.0]alkanes and 2-halobenzobicyclo[n. 1. OJalkenes by tributyltin hydride, with photochemical initiation, led to the formation of 3-methylcycloalkenes. The substrates 15129,18129 2129.74... 

The feasibility of a radical attack on the carbon atom of isonitriles was then claimed by Saegusa [4], who studied the reaction of tributyltin hydride with alkyl isonitriles. Formation of alkane and tributyltin cyanide, together with the need for a... 

Full details have appeared of the deoxygenation of alcohols to alkanes by tripropylsilane reduction of their chloroformate esters (2,122). In a related procedure, alcohol selenocarbonates (69), prepared from the chloroformate esters, have been reduced to alkanes by tributyltin hydride. Both are believed to be radical-chain reactions. Primary allylic alcohols have been deoxygenated to terminal alkenes by the new stannylation-protodestannylation sequence shown in Scheme 32 the S-Sn exchange is another radical process. The intermediate allylstannanes may alternatively undergo a new oxidative destanny-lation as shown to give overall [l,3]-transposition of the allylic alcohol. ... 

Tributyltin hydride has been applied to the selective reduction of acid chlorides and 1,3-dithiolanes/ and to the conversion of carboxylic acids and isocyanides " to alkanes. Acyl cyanides are obtained from the treatment of acid chlorides with tributyltin cyanide/ and cyclic ketones are converted into nitro-olefins via the corresponding trimethylvinyltin compound. ... 

The Baiton-McCombie reaction describes the overall reduction of a 1°, 2°, or 3° alcohol (1) to the parent alkane (3), effectively replacing -OH with -H. Reduction is achieved via pre-activation of the hydroxyl group as its thiocarbonyl derivative (2) followed by reaction with a reducing agent such as tributyltin hydride. The reductive process involves a radical-mediated transformation. 

A radical initiator, such as azobisisobutyronitrile (AIBN, 7) decomposes homolytically under reaction conditions to generate 8 which abstracts a hydrogen from tributyltin hydride (9) creating a tin-centered radical 10. The tin radical attacks at the sulphur atom of the thiocarbonyl derivative 2, generating intermediate 11 which collapses leaving tributyltin xanthate 12 (which can further decompose to 0=C=S and 13) and alkyl radical 14. Intermediate 14 can abstract another atom of hydrogen from tributyltin hydride to generate the desired alkane product 3, and replenish the pool of tin radical 10. 

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