Less Toxic Organotin Reagents

This reaction unfortunately requires stoichiometric monoorganotin trihalide and suffers from poor atom economy and effective mass yield. 

Nano-tin is prepared by reduction of SnCL with isopropanol and irradiation under ay-ray source ( °Co) and has a particle size of 20-30 nm. Allylation of aromatic aldehydes in water are almost quantitative and reaction times are reduced from 8-24 hours for regular tin powder to 1.5-8 hours. Aliphatic aldehydes 

The reaction involves stirring aldehyde, allyl bromide, and stannous chloride in water and applying an electrolytic potential of 2.0 V with graphite electrodes. The cathode rednces Sn(ll or IV) salts to tin metal, which react with allyl bromide to generate allyltin(ll) bromide and diallyltin dibromide. These organotin species then allylate the aldehyde and the resulting homoallyl alcohol is extracted with diethyl 

It is an aim of green chemistry (and good synthetic chemistry) to introduce as much useful functionahty as possible in the minimum number of steps. Unfortunately, this multi-component cascade couphng requires the use of anhydrous organic solvents. Nevertheless, it can be envisaged that the greener nanotin and electrochemical approaches described above could possibly be extended to this type of cascade sequence. 

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