STEREOSELECTIVE TRANSFORMATIONS WITH CONFIGURATIONALLY LABILE ALPHA-PHENYLSELENOALKYLLITHIUM COMPOUNDS

Complexation of the configurationally labile alpha-phenylselenoalkylli thium compound 8 with 1,2-bisdimethylaminocyclohexane 15 led to two di astereomeric complexes 13 and 14 in a 7:3 ratio. Owing to ligand accel eration the complexes 13 and 14 added more rapidly to benzaldehyde tha n the uncomplexed organolithium compound 8. Trapping of complexes 13 a nd 14 by benzaldehyde was shown to occur more rapidly than their equil ibration. This corresponds to non-Curtin-Hammett kinetics, in which en antiomeric enrichment in the products reflects the equilibrium ratio o f the complexes 13 and 14.