Since it can be expected that a chiral center being
in close proximity to a prochiral reaction center will
exhibit the strongest influence, there is an overwhelming
number of examples for 1,2-induction, and
consequently, models to explain such diastereoselectivity
have been most prominent in the literature.
The fundamental models such as the Cram and the
Felkin-Anh rule can be found today in almost every
organic textbook; nevertheless, the underlying concepts
still form the basis for further modifications,
and extensions are applied to current research problems.