The influence of a chiral center on a prochiral reaction center within the same molecule is one of the fundamental stereochemical issues addressed in organic synthesis. Ever since D. J. Cram1 outlined almost 50 years ago an edifice to explain the stereoselectivityin the addition of nucleophiles to R-chiral carbonyl compounds, which became known as the
Cram rule,2 a fabric was created which proved to be most fruitful in understanding, predicting, and controlling
diastereoselectivity induced by a remote