Solvation of the Carbonyl Compound as a Predominant Factor in the Diastereofacial Selectivity of Nucleophilic Addition.
Temperature-dependent selectivity in nucleophilic additions is affected by the solvent. The inversion temperature (marked with arrows in the graph) that appears in the nonlinear Eyring plots of ln (anti/syn) versus temperature for the addition of butyllithium to an O-protected alpha-hydroxy aldehyde 1 does not depend on nucleophiles (nBuLi (black triangle), tBuLi (*)), but on the solvent. Its value can be obtained from a plot of the (13)C NMR chemical shift of C=O versus temperature. TBDMS=tBuMe(2)Si.
Cainelli
G
Dipartimento di Chimica "G. Ciamician" Via Selmi 2, 40126 Bologna (Italy).
Galletti
P
Giacomini
D
Orioli
P