Organotin dihydrides

Hydrosilation of an alkenylsilane in the presence of a catalyst provides a route to five-, six- and seven-membered rings but is of little use for the smaller ones. Tin-substituted cyclohexa-2,5-dienes result directly from the a,[Pg.575]

N. M. Weinshenker, G. A. Crosby, and J. Y. Wong, Polymeric Reagents. IV. Synthesis and utilization of an insoluble polymeric organotin dihydride reagent, J. Org. Chenx. 40 1966 (1975). 

The polymer-supported organotin dihydride 70 was shown to be an efficient reducing agent for aldehydes and ketones, but substantial loss of activity was observed after regeneration. More recently, various polymer-supported butyltin reagents (71, 72) were studied as reagents for the acetylation of sucrose158. 

Regeneratable polymeric organotin dihydride beads have been used to reduce halides selectively (e.g. 3-bromocamphor to camphor).52 /3-Unsubstituted cyclohex-enones undergo exclusive and almost quantitative 1,4-reduction by potassium tri-s-butylborohydride to the corresponding saturated ketone [e.g. (16)] 53 reductive alkylation of carvone proceeds similarly to (17 R = Me, X = H).53 In contrast,... 

Polymeric Organotin Dihydride Reagent as a Reducing Agent... 

The versatility and selectivity of organotin hydride, is well documented. The use of polymeric organotin dihydride reagent involves ease of operation and reaction workup and avoids toxic vapours, characteristic of tin hydride. 

The polymer supported organotin dihydride reagent has been used ° for the conversion of aldehydes and ketones to alcohols in 80-90% yields and the reduction of halides to hydrocarbons. The use of organotin hydride for the reduction of alkyl and aryl halides in presence of other functional groups is generally superior to lithium aluminium hydride. This can also be used for the selective reduction of only one functional group of a symmetrical difiinctional aldehyde (terephthaldehyde). 

A number of miscellaneous organotin polyolefins have been produced. Treatment of tin halides or organotin halides with olefins, aluminum, and hydrogen at elevated temperatures produced materials of the general form as structure 54. Addition reactions involving organotin dihydrides and diolefins have been used to produce organotin polyolefins of structure 55 (eq. 

Weil975 Weinshenker, N.M., Crosby, G.A. and Wong, J.Y, Polymeric Reagents. FV. Synthesis and Utilization of an Insoluble Polymeric Organotin Dihydride Reagent, J. Org. Chem., 40 (1975) 1966-1971. 

Noltes and van der Kerk have exploited the reaction of organotin dihydrides with bifunctional unsaturated compounds as a means of preparing polymers containing tin atoms in the backbone of the chain 37, 59, 61). 

Dienes and Diynes Which Have Been Shown to React with Organotin Dihydrides... 

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