Determination of the Composition of Isomeric Mixtures of Allylstannanes by Means of 119Sn and 13C NMR Measurements

Allylstannanes of the type Bu3nSn(C3H3) (C3H3-allenyl and propargyl) Me3Sn(C4H7), Bu3nSn(C4H7), Ph3Sn(C4H7), Me2Sn(C4H7)2 and Bu2nSn(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 Sn-119 and C-13 NMR spectrometry. The Sn-119 and C-13 delta-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 Sn-119 NMR spectrometry