Stereoselective Transformations with Configurationally Labile α‐Phenylselenoalkyllithium Compounds

Complexation of the configurationally labile α‐phenylselenoalkyllithium compound 8 with 1,2‐bisdimethylaminocyclohexane 15 led to two diastereomeric complexes 13 and 14 in a 7:3 ratio. Owing to ligand acceleration the complexes 13 and 14 added more rapidly to benzaldehyde than the uncomplexed organolithium compound 8. Trapping of complexes 13 and 14 by benzaldehyde was shown to occur more rapidly than their equilibration. This corresponds to non‐Curtin–Hammett kinetics, in which enantiomeric enrichment in the products reflects the equilibrium ratio of the complexes 13 and 14.