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Regioselective ortho ‐Metallation of 2‐Diphenylphosphanylpyridine and (2‐(2‐Diphenylphosphanyl)phenyl)‐1‐3‐dioxalane with Methyltetrakis(trimethylphosphane)cobalt(I)
Author(s) -
Beck Robert,
Sun Hongjian,
Li Xiaoyan,
Klein HansFriedrich
Publication year - 2009
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200800309
Subject(s) - chemistry , regioselectivity , stereochemistry , octahedron , substituent , cobalt , steric effects , oxidative addition , medicinal chemistry , pyridine , ring (chemistry) , carbon monoxide , crystal structure , crystallography , organic chemistry , catalysis
Co(CH 3 )(PMe 3 ) 4 forms 100 % regioselectively with (2‐(2‐diphenylphosphanyl)phenyl)‐1,3‐dioxalane and 2‐diphenylphosphanyl‐pyridine, by elimination of methane, the four‐membered metallacycles Co{(C 3 O 2 HC 6 H 3 )P(C 6 H 5 ) 2 }(PMe 3 ) 3 ( 1 ) and Co{(CNC 4 H 3 )P(C 6 H 5 ) 2 }(PMe 3 ) 3 ( 4 ). The regioselectivity is independent of the steric requirement of the ortho substituent in the 2‐diphenylphosphanylaryl‐ligands. Oxidative addition with iodomethane transforms 1 and 4 into octahedral, diamagnetic low‐spin d 6 complexes Co(CH 3 )I‐{(C 3 O 2 HC 6 H 3 )P(C 6 H 5 ) 2 }(PMe 3 ) 2 ( 2 ) and Co(CH 3 )I‐{(CNC 4 H 3 )P(C 6 H 5 ) 2 }(PMe 3 ) 2 ( 5 ). Under an atmosphere of carbon monoxide, insertion into the Co‐C bond results in ring expansion by forming the new assembled phosphanylbenzoyl complexes Co{(C 4 O 3 HC 6 H 3 )‐P(C 6 H 5 ) 2 }CO(PMe 3 ) 2 ( 3 ) and Co{(OCNC 4 H 3 )P(C 6 H 5 ) 2 }CO(PMe 3 ) 2 ( 6 ). The three different types of cobaltacycles are supported by X‐ray diffraction of 1 , 3 , 5 and 6 .