106993-05-9Relevant academic research and scientific papers
TRIMETHYLSTANNYLLITHIUM MEDIATED SYNTHESIS OF 2-, 3- AND 4-TRIMETHYLSTANNYLCYCLOHEXANOLS
Ricci, Alfredo,Taddei, Maurizio,Seconi, Giancarlo
, p. 23 - 28 (1986)
The use of trimethylstannyllithium for the preparation of 2-, 3- and 4-trimethylstannylcyclohexanols is described.The stereochemistries of these products are discussed on the basis of the 1H, 13C, and 119Sn NMR data.
Silicon and tin-directed Tiffeneau-Demjanov reaction
Chow, Leonie,McClure, Melanie,White, Jonathan
, p. 648 - 650 (2007/10/03)
Silicon and tin substituents surprisingly have only a moderate directing effect on the Tiffeneau-Demjanov reaction. The low selectivity is rationalised as being due to the reactive nature of the diazonium ion leaving group, the weaker oxydiazene leaving g
The γ and δ effects of tin
Lambert, Joseph B.,Salvador, Lourdes A.,So, Jeung-Ho
, p. 697 - 703 (2008/10/08)
The trimethylstannyl group either γ (four bonds) or δ (five bonds) from a tosylate leaving group in the simple cyclohexane framework can alter the mechanism from nucleophilic assistance by solvent to intermediacy of a hyperconjugatively stabilized carbocation. The mechanistic change is indicated by rate accelerations (compared with the analogous ring lacking tin), by stereochemical dependence, by insensitivity to solvent nucleophilicity, by sensitivity to solvent ionizing power, by products resembling the hyperconjugative resonance structure, and (in the δ case) by the α-deuterium kinetic isotope effect. For the γ effect, stabilization of the carbocation occurs when tin is anti-anti to the leaving group (W geometry) and involves homohyperconjugation or cyclopropyl-(no-bond) conjugation. For the δ effect, stabilization occurs when tin is anti-gauche-anti (zigzag) to the leaving group and involves double hyperconjugation, i.e., (double-bond)-(no-bond) conjugation twice over. These results extend the concepts of delocalization of positive charge over σ bonds within the simple cyclohexane ring.
