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Efficient Asymmetric Synthesis of Planar‐Chiral Bisferrocenes
Author(s) -
Enders Dieter,
Jonas Eric Alexander,
Klumpen Thomas
Publication year - 2009
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.200900015
Subject(s) - metalation , chemistry , surface modification , methylene , transmetalation , medicinal chemistry , stereochemistry , organic chemistry , combinatorial chemistry , catalysis
SAMP auxiliary‐derived monosubstituted diferrocenyl ketones have been subjected to ortho ‐metalation/functionalization reactions to prepare chiral disubstituted bisferrocenes. The reactions proceeded in low to moderate yields (20–54 %) and excellent stereoselectivities (97 – ≥ 99 % ee , ≥ 96 % de ), however low regio‐selectivities were obtained in several cases. Monosubstituted bisferrocenes, containing only a planar‐chiral element, were excellent substrates in the same ortho ‐metalation/functionalization reaction affording disubstituted bisferrocenes in moderate to excellent yields (39–99 %) and generally excellent levels of asymmetric induction (≥96 % de ) with complete regiocontrol. The synthesis of related methylene‐bridged mono‐ and di‐substituted diferrocenyl ligands containing N ‐, O ‐, P ‐ and/or S ‐donor atoms is also described.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)