Superbase metalation of alkenes or alkylbenzenes and subsequent condensation with trialkylstannyl chloride affords allyl- or benzyl-type organotin compds. that can be isolated in pure form. Treatment with sol. reagents such as methyllithium, trimethylsilylmethylpotassium and trimethylsilylmethylcesium generates the corresponding organoalkali derivs., almost quant. and in high purity, suitable for kinetic or spectroscopic studies. E.g., treating Me3SiC(:CH2)Me with KOCMe3 and BuLi in THF and then with Me3SnCl gave 45% CH2:C(SiMe3)CH2SnMe3, which when treated with Me3SiCH2Cs gave 95% of the Cs deriv. [on SciFinder (R)]