Determination of the composition of isomeric mixtures of allylstannanes by means of 119Sn and 13C NMR measurements

Abstract Allylstannanes of the type Bun3Sn(C3H3) ((C3H3 = allenyl and propargyl) Me3Sn(C4H7), Bun3Sn(C4H7), Ph3Sn(C4H7), Me3Sn(C4H7)2 and Bun3Sn(C4H7)2 [C4H7 = (E)-but-2-enyl, (Z-but-2-enyl, and but-1-en-3-yl] were prepared via Grignard reactions as isomeric mixtures whose compositions can be directly determined by 119Sn and 13C NMR spectrometry. The 119Sn and 13C δ-values of all possible isomers together with the isomeric compositions of freshly prepared compounds and after isomerization in dry methanol under reflux are reported. The course of isomerization of some compounds in anhydrous methanol at room temperature or in the presence of Bu3SnCl was followed by 119Sn NMR spectrometry.