Complex-induced proximity effects: stereoselective carbon-carbon bond formation in chiral auxiliary mediated beta-lithiation-substitution sequences of beta-substituted secondary carboxamides

Research was conducted to test the complex-induced proximity effect hypothesis which states that remote groups can influence the development and reactivity of organolithium intermediates. Using the synthesis of an enantiomerically pure four-substituted dihydrocoumarin, it is shown that the chiral homoenolate equivalents act as nucleophiles for diastereoselective carbon-carbon bond-forming reactions. The method presents an alternative to alpha-hereoatom allylithium complexes.