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Explanation of Different Regioselectivities in the ortho ‐Lithiation of Ferrocenyl(phenyl)methanamines
Author(s) -
Almássy Ambroz,
Škvorcová Andrea,
Horváth Branislav,
Bilčík Filip,
Bariak Vladimír,
Rakovský Erik,
Šebesta Radovan
Publication year - 2013
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201201325
Subject(s) - chemistry , dilithium , stereocenter , intramolecular force , moiety , ring (chemistry) , ferrocene , lithium atom , lithium (medication) , stereochemistry , ligand (biochemistry) , carbanion , carbon atom , medicinal chemistry , enantioselective synthesis , ion , organic chemistry , catalysis , medicine , biochemistry , receptor , electrode , endocrinology , deprotonation , electrochemistry , ionization
Diastereoselective ortho ‐lithiation of ferrocenes is a principal strategy for the synthesis of chiral ferrocene ligands. Dilithiation of ( R )‐1‐(2‐bromophenyl)‐1‐ferrocenyl‐ N , N ‐dimethylmethanamine leads to a dilithium intermediate, which can be transformed to a Taniaphos ligand with ( R , R p )‐configuration. On the other hand, lithiation of ( R )‐1‐phenyl‐1‐ferrocenyl‐ N , N ‐dimethylmethanamine affords a lithiated product with opposite configuration of the stereogenic plane. Presumably, the second lithium atom attached at the ortho ‐position of the phenyl ring is responsible for this difference through the intramolecular multicenter arrangement involving both lithium atoms and their adjacent carbon atoms, the iron atom of the ferrocenyl moiety, and the nitrogen atom of the amino group. This hypothesis has been supported also by quantum chemical calculations.