Organotin Alkoxides and Halides

Organotin alkoxides and phenoxides can be prepared from the reaction of an alkali metal alkoxide or phenoxide with the appropriate organotin halide. Triorganotin alkoxides and phenoxides are available from the reaction of bis(triorganotin) oxides with alcohols or phenols or the corresponding carbonates, and the amides R Sn(NR"2)4 react with alcohols to give the corresponding alkoxides. 

The structures of organotin amines and alkoxides are tetrahedral, as expected. Organotin alkoxides and phenoxides are prepared from reaction with alcohols and alkali metal alkoxides or phenoxides with the organotin halide. Most of the published reactions occur in the liquid phase. For instance, the dimethoxide is formed from reaction of dibutyltin dichloride in methanol at 0°C in 98% yield. ... 

Simple organotin alkoxides or phenoxides are available from the halides on reaction with MOR or MOAr, as well as from the oxides and the alcohol or phenol on azeotropic dehydration. These compounds are generally sensitive to H2O and to CO2. Cyclic alkoxides, e.g. (51) and (52), and cyclic diaUcoxides from diols, e.g. (53), can also be prepared. These complexes are usually oligomeric. 

Two other methods involve reacting organotin halides with germyl-Hg compounds (see 5.7.5.3) and organotin alkoxides with silyl-Hg compounds (see 5.7.5.4). 

These compounds are most readily obtained by hydrolysis of organotin halides, especially under basic conditions, although hydrolysis of alkoxides and amides, etc., can also be used. Hydrolysis of di- and trihalides occurs in a stepwise fashion and various of the partial hydrolysis products have been characterized (Scheme 19). 

This early work is summarised in Krause and von Grosse s Organometallische Che-mie which was published first in 1937,11 and which described examples of tetraalkyl-and tetraaryl-stannanes, and of the organotin halides, hydrides, carboxylates, hydroxides, oxides, alkoxides, phenoxides, R2Sn(II) compounds (incorrectly), distannanes (R3SnSnR3), and oligostannanes (RiSn) . 

Organotin esters of the oxy- and thio-acids of phosphorus can be prepared inter alia by azeotropic dehydration of a mixture of the organotin hydroxide or oxide and the acid, or by treating a tin alkoxide or tin amide with the acids, or an organotin halide with a salt of the phosphorus acid. By using different molecular ratios of the reactants, products of different compositions can be obtained. Attempts to prepare phosphites may result in an Arbuzov rearrangement to a phosphorus(V) compound (e.g. equation 13-11).47... 

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