Diphenyltin dihydride

The mixed halide-hydrides PhjSnHCl and PhjSnHBr have been prepared from the reaction of diphenyltin dihydride with the appropriate diphenyltin dihalides (274). 

In a modification of this method, the Sn-0 bonded compound can be generated in situ by partial acidolysis of a tin hydride, and, from the reaction between diphenyltin dihydride and carboxylic acids, a number of l,2-bis(acyloxy)-l,l,2,2-tetraphenylditins, (RC02)Ph2SnSnPh2(02CR) (e.g., R = CHj, CF3, PhaSi, or PhjGe), have been prepared (257, 258). 

Diphenyltin dihydride, (C6H5)2SnH2,1, 349. The reagent is prepared in situ by reaction of (C6H5)2SnCl2 with LiAlH4 (1 equiv.) in ether. 

REDUCTION, REAGENTS Aluminum amalgam. Borane-Dimethyl sulfide. Borane-Tetrahydrofurane. t-Butylaminoborane. /-Butyl-9-borabicyclo[3.3.1]nonane. Cobalt boride— f-Butylamineborane. Diisobutylaluminum hydride. Diisopropylamine-Borane. Diphenylamine-Borane. Diphenyltin dihydride. NB-Enantrane. NB-Enantride. Erbium chloride. Hydrazine, lodotrimethylsilane. Lithium-Ammonia. Lithium aluminum hydride. Lithium borohydride. Lithium bronze. Lithium n-butylborohydride. Lithium 9,9-di-n-butyl-9-borabicyclo[3.3.11nonate. Lithium diisobutyl-f-butylaluminum hydride. Lithium tris[(3-ethyl-3pentylK>xy)aluminum hydride. Nickel-Graphite. Potassium tri-sec-butylborohydride. Samarium(II) iodide. Sodium-Ammonia. Sodium bis(2-mcthoxyethoxy)aluminum hydride. 

Diphenyltin dihydride, 224 Diphosphorus tetraiodide, 224-225 (+ )-Di-3-pinany Iborane, 225-226 Diprenyl ether, 160 Dipyridinc chromium(VI) oxide, 139 DisiamyIborane, 226 N,N -Disuccinimjdyl carbonate, 226-227... 

Similarly, 1,2,3,4,7,7-hexachloronorbornene (91, X = Cl) and l,2,3,4-tetrachloro-7,7-dimethoxynorbornene (91, X = OMe) are hydrogenated without losing the allylic chlorines in the hydrogenation over Pd-C in ethanol in the presence of triethylamine only the vinylic chlorines are removed (eq. 13.125).225 The 7,7 bridge chlorines of the product may be further reduced to 1,4-dichloronorbornane by diphenyltin dihydride in diglyme at 110-120°C. 

Diphenyltin dihydride reduces aldehydes and simple ketones to alcohols in yields of about 80%, and the reaction differs from reduction with a metal hydride in that a >C=0 + (CsHjljSnHj ------------------------- CHOH + CsHsljSn... 

Diphenyltin dihydride, (CeH5)2SnH2,1, 349. Supplier Alfa Inorganics. 

Diphenyltin dihydride was found to be effective for reduction of 1,4,7,7-tetrachloronorbomane (1) to 1,4-dichloronorbomane (2). Use of tri-n-butyltin hydride led only to reduction to 1,4,7-trichloronorbomane.2... 

To a flask containing 5.28 gm (0.0314 mole) of A(A -ethylene bis-acrylamide in 40 ml benzene is added 8.63 gm (0.0314 mole) of diphenyltin dihydride and the mixture is heated to reflux. After 5-hr refluxing the benzene is removed under reduced pressure and the residue heated at 95°C for 4 hr. The infrared spectrum of the solid indicated no free Sn—H absorption. The product is extracted with acetone for 6 hr to remove low-molecular-weight species and then the residue is dissolved in DMF. The DMF solution is centrifuged and then evaporated to chyness to afford 8.3 gm (60 /o) of polymer (m.p. 110 -120 C). 

The related additives of diphenyltin dihydride with ethylene glycol dimetha-crylate gave a A/w of 150,000. 

The addition of diphenyltin dihydride to diacetylenic compounds is also reported to give polymers. 

By addition of diphenyltin dihydride to diphenyldistyrenelead, polymers containing lead in the main chain were obtained 209). 

An ethereal soln. of diphenyltin dichloride added at —5° to an ethereal soln. of diethylaluminum hydride, and stirred 2 hrs. at —20° -> diphenyltin dihydride. Y 81%. Neumann and H. Niermann, A. 653,... 

Diphenyltin dihydride (Ph2SnH ). Using the procedure described above, reaction of 3.4g of diphenyltin dichloride (Research Chem.) and l.lg of lithium aluminium hydride gave 2.1g (75% yield) of a clear liquid (lit. bp 89-93°C/0.3 Torr) with the following characteristics 1.6127 (lit. 1.595 IR 1865 cm (Sn-H)(lit. 

Diphenyltin dihydride reacts with the vinyltriphenyl metals of silicon, germanium, and tin in an abnormal manner. Instead of the expected product, I, Compound II is formed in yields of 20-25 %. 

Two isomers, presumably with the phenyl groups cis and trans to each other, were obtained in comparable yields. o-Divinylbenzene and diphenyltin dihydride react to form l,l-diphenyl-4,5-benzo-l-stannacycloheptene (IV), a trimer to which a cyclic structure has been assigned, and polymer (59). The reaction of 1,5-hexadiyne with R2SnH2 yielded 12% to 28% of the stannepin (V), when R was CH3, C2H5, n-C3H7, and C Hs (57). Dibenzo analogs (VI) have been prepared previously by a more laborious sequence of reactions 60). 

The first of these methods with di- -butyltin or di- -propyltin hydride and phenylacetylene gives a viscous oil in the latter case the average value of is 11 37,59). The polymeric adduct which is formed in the corresponding reaction involving diphenyltin dihydride is a hard, brittle solid (59). 

Cyclopentadiene appears to be the only conjugated diene which has been used. It reacts with di-w-propyltin or diphenyltin dihydride to form a one-to-one adduct, whose structure has not been described (59). The other adducts involving di- -propyltin dihydride, for example, range from viscous oils, to soft and tacky, tough, or rubbery substances, depending on the diene used. A list of the dienes is contained in Table VI. 

The first observation, of the reduction of a ketone by an organotin hydride appears to have been the result of an attempt to carry out the hydrostarma-tion of 2 moles of methyl vinyl ketone by 1 mole of diphenyltin dihydride (63, 64). Instead of the expected adduct the products were pol5rmeric diphenyltin, which precipitated during the reaction, and methyl vinyl carbinol, Eq. (32). This reaction is surprising because the alcohol is isolated... 

Among the other simple compounds reduced by diphenyltin dihydride are cyclohexanone (82%), benzaldehyde (62%), mesityl oxide (60%), and chalcone (75%). It can be seen that the yields are high with the simple ketones and aldehydes, and moderate in the case of the a,]8-unsaturated analogs. The cause of the lower yields has not been examined, but may be due to the occurrence of hydrostannation, particularly of the product alcohol, as a side reaction. In all of these cases the unsaturated alcohol was the reduction product the double bond was not reduced. The same is true when triphenyltin hydride is used in the reduction of methyl vinyl ketone and phenyl vinyl ketone 66). 

Reductions of several ketosteroids by diphenyltin dihydride have been examined as a means of discovering what kind of selectivity exists among carbonyl groups in a given molecule (67). Pregnenolone (VII) was reduced at C-3 in preference to C-20 in a ratio of about 6.5 to 1. This result stands in marked contrast to the fact that sodium borohydride reduces the keto group... 

C-3 and C-20. Thus the reduction process is extremely sensitive to the change in hybridization at C-11, which is remote from both the carbonyl groups. The C-11 carbonyl in cortisone is highly hindered, and is unaffected by diphenyltin dihydride even when used in excess. A similar effect of steric bulk shows up in the case of camphor, which could not be reduced in satisfactory yield with either diphenyltin dihydride or di-n-butyltin dihydride under conditions which lead to facile reduction of simple cyclohexanones 63). 

Reactions of Diphenyltin Dihydride with RCOOH to Form 1,1, 2,2-Tbtraphenyl-1, 2-diacyloxyditins... 

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