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Chiral Arene Ruthenium Complexes, 2 A Diastereoselective Route to [η 6 ‐Benzyl Alcohol)(COD)Ru] Complexes
Author(s) -
Bodes Gegro,
And Frank Heinemann,
Zenneck Ulrich
Publication year - 1997
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19971300923
Subject(s) - chemistry , diastereomer , aldehyde , ketone , stereocenter , steric effects , alcohol , ruthenium , medicinal chemistry , benzyl alcohol , lithium (medication) , stereochemistry , enantioselective synthesis , organic chemistry , catalysis , medicine , endocrinology
Two preparative routes are reported that give access to the racemic series of planar chiral [(arene)(COD)Ru] derivatives containing η 6 ‐bonded o‐tolyl ketone or aldehyde arene units. The ketone and aldehyde functions of these have subsequently been reduced by n BuLi and PhLi, respectively. Hydrolysis converts the initially formed lithium salts into diastereomeric benzyl alcohol complexes lithium salts into diastereomeric benzyl alcohol complexes in high yields. The formation of the new stereogenic centre is diastereoselective (88% de) for the aldehyde and diastereospecific for the ketone (de > 99%). Due to a sterically overcrowded situation, the rotation of the chiral side chain of [(COD) (η 6 – o ‐tolyl‐tert‐butylphenylmethanol) Ru] ( 7 ) is hindered, as is the rotation of the phenyl and tert ‐butyl substituents. As a consequence, the hydroxyl group is fixed at a position close to the metal both in solution and in the solid state.