Dibutyltin bis-

Mercaptides are unchallenged as the ligand of choice for the other entities bonded to the tin, but carboxylates can also be used. Whereas a variety of mercaptans are used, the thioglycolic acid derivatives remain the largest single mercaptan. Dibutyltin bis(isooctyl thioglycolate) [25168-24-5] and butyltin tris(isooctyl thioglycolate) [25852-70A] are two common examples. These materials are produced by the reaction of the appropriate alkyl tin chloride or oxide, and the mercaptan. 

Mukaiyama aldol reactions have been reported, usually using chiral additives although chiral auxiliaries have also been used. This reaction can also be run with the aldehyde or ketone in the form of its acetal R R C(OR )2> in which case the product is the ether R COCHR2CR R OR instead of 27. Enol acetates and enol ethers also give this product when treated with acetals and TiCLi or a similar catalyst. When the catalyst is dibutyltin bis(triflate), Bu2Sn(OTf)2, aldehydes react, but not their acetals, while acetals of ketones react, but not the ketones themselves. 

Reaction with RCHO and acetals.1 In the presence of dibutyltin bis(tri-fiuoromethanesulfonate), 2,3 this reagent converts aldehydes or their dialkyl acetals or ethylene acetals into 2-alkyl-1,3-dithianes (70-85% yield). However, the reagent differentiates between aldehydes and acetals as shown in the examples. An aliphatic... 

Dodecyl 4-pent-2-enyl Sulfide. Dibutyltin oxide (21.37 grams, 0.08589 mole) reacted with 34.7 grams (0.1715 mole) of dodecyl mercaptan in 150 ml. of toluene at reflux for 39 minutes when the evolution of water had ceased. The reaction product was charcoaled, filtered, and concentrated to constant weight at 55 °C. and < 1 mm. The yield of colorless dibutyltin bis(dodecylmercaptide) was 54.7 grams (theory 54.53 grams). This mercaptide, 1.5023 grams (0.00494 mole) of dibutyltin dichloride, and 17.96 grams (0.1718 mole) of 4-chloro-2-pentene reacted in 250 ml. chlorobenzene solution for 7.2 hours when analysis of a sample of the reaction product for chloride showed the reaction to be virtually completed. 

The first term represents the unimolecular decomposition of allylic chloride. The first and fourth terms are responsible for hydrogen chloride elimination and do not result in stabilization. The second and third terms are responsible for stabilization. This work has provided an estimate of the rate constants for dibutyltin dilaurate and dibutyltin bis (monobutyl maleate). 

The behavior of dibutyltin bis(dodecylmercaptide) on reaction with 4-chloro-2-pentene proved interesting (Figure 3). With only the two reactants in chlorobenzene, virtually no reaction took place up to 5 hours. However, the addition of dibutyltin dichloride resulted in a rapid reaction. Furthermore, the addition of a few milligrams of azobisisobutyro-nitrile eliminated any induction period. This latter consequence is not interpreted to result from a free radical stabilization mechanism, but it is presumed to be caused by free radical-catalyzed hydrogen chloride elimination, resulting (by neutralization with the stabilizer) in the formation... 

Figure 4. RCl vs. time for the reaction of 4-chloro-2-pentene with dibutyltin bis(monobutylmaleate) at 80° C. Letters L, /, N, M designate different...

Table VI. Reaction of Dibutyltin Bis(monobutylmaleate) With 4-Chloro-2-pentene at 80°C.

Estimates of the rate constants for dibutyltin dilaurate and for dibutyltin bis(monobutylmaleate) are reported. 

Bu2Sn (OCOCH=CHCOOR) 2 Dibutyltin bis (isooctyl maleate)... 

SYNS DIBUTYLBIS((2-ETHYLHEXANOYL)OXY)-STANNANE DIBUTYLBIS((2-ETHYL-1-OXOHEXYL)OXY)-STANNANE (9CI) DIBUTYLTIN BIS(a-ETHYLHEXANOATE) DIBUTYLTIN BIS(2-ETHYLHEXANOATE) DIBUTYLTIN DI(2-ETHYLHEXANOATE) DI-n-BUTYLTIN DI-2-ETHYLHEXANOATE DIBUTYLTIN DI(2-ETHYLHEXOATE)... 

SYNS DIBUTYISIS((3-CARBOXYACRYLOYL)OXY)-STANNANE DIMETHYL ESTER (Z,Z) (SCI) DIBUTYLTIN BIS(METHYL MALEATE) DIBUTYLTIN BIS(MONOMETHYL MALEATE) DIBUTYLTIN METHYL MALEATE 6,6-DIBUTYL-4,8,lI-TRIOXO-5,7,12-TRIOXA-6-STANNATRlDECA-2,9-DIENOIC ACID METHYL ESTER DI-n-BUTYLZINN-DIMONO-METHYLMALEINAT (GERMAN) STAN-GUARD 156... 

DIBUTYLTIN BIS(METHYL MALEATE) see BKO250 DIBUTYLTIN BIS(MONOMETHYL MALEATE) see BKO250... 

Cadmium/zinc phosphite esters are also effective light stabilizers, as are WO3 and rare-earth-metal oxides. " Dibutyltin bis-isooctylthioglycolate is converted into the corresponding dibutylmonochlorotin ester and SnOCl2 during irradiation in PVC. ... 

The authors apphed this new concept to chemoselective functionalization of carbonyls rather than acetals [194], which is usually quite difficult to achieve because of the high reactivity of the acetal counterparts with Lewis acids. Reaction of a mixture of 1 equiv. each of acetophenone and its dimethyl acetal with ketene silyl acetal 191 under the influence of bidentate aluminum Lewis acid 188 in CH2CI2 at -78 °C for 3 h afforded aldol products 195 exclusively (88 % yield). It is worth noting that employment of dibutyltin bis(triflate) (DBTT) (10 mol%) as catalyst [195], which is quite useful for activation of aldehyde carbonyls rather than acetals, gave unsatisfactory results, producing the y3-methoxy ester preferentially (Sch. 147). 

Dibutyltin bis(triflate), Bu2Sn(OTf)2, is a mild Lewis acid which catalyzes clean Michael addition of enol silyl ethers [148]. The new catalyst enables use of various labile acceptors such as methyl vinyl ketone and 2-cyclopentenone which do not undergo smooth reaction with conventional Lewis acids. A variety of enol silyl ethers are also employable and thus 2-(trimethylsiloxy)propene, the simplest of this class of compounds, can be used. The adducts of enol silyl ethers of cycloalkanones with vinyl ketones are readily cyclized to give the desired annulated enones free of isomers. Consequently, a practical version of the Robinson annulation has been realized. 

Borylated myo-inositol 128 was transmetallated with dibutyltin-bis(acetylacetonate) (1 equiv) to afford the butyltin derivative, which was then treated with (-)-menthyl chloroformate (1.3 equiv.) and 7 7-methyl imidazole to give a 2 1 (70% yield) mixture of 129a and... 

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