Interet de la deuteriation des molecules organostanniques en rmn de 119Sn : I. Acces aux constantes de couplage nJ(SnD) et application a l'etude structurale de vinyl et d'allyletains

The selective deuteration of organotin compounds gives FT ¹¹⁹Sn NMR a new proficiency, since it allows direct access to ⁿJ(SnD) coupling constants. Usually ⁿJ(SnD) is easily apparent for n  1, 2, 3 and sometimes 4 (allyltin compounds). This criterion has been successfully applied for qualitative and subsequently quantitative analysis of vinyltin and allyltin compounds.In the first series, the stereochemistry of alkyne deuterostannation has been easily explored, the assignments of configurations being made directly from ³J(SnD) on the basis of ³J(SnD)_trans > ₃J(SnD)_cis. In the second series, the method appears to be the best tool for simultaneous study of regiochemistry and stereochemistry in the substitution of 3-deutero-5-methyl-2-cyclohexenyl toluene sulphonates by trialkylstannyl anions. The choice between regioisomers was made on the basis of ₂J(SnD) >- ⁴J(SnD).A further aspect of this work is the observation of isotopic effects on ¹¹⁹Sn chemical shifts which were tentatively rationalized considering inductive, steric or hyperconjugative contribution of deuterium.