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Unusual Anion Effects in the Iron‐Catalyzed Formation of 3‐Hydroxyacrylates from Aromatic Aldehydes and Ethyl Diazoacetate
Author(s) -
Alves Luis Gonçalo,
Dazinger Georg,
Veiros Luis F.,
Kirchner Karl
Publication year - 2010
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201000240
Subject(s) - chemistry , counterion , ethyl diazoacetate , catalysis , chemoselectivity , medicinal chemistry , ion , organic chemistry , cyclopropanation
Due to the lability of one of the CO ligands in trans ‐[Fe(PNP)(CO) 2 Cl] + this compound is an efficient catalyst for the coupling of a series of aromatic aldehydes with ethyl diazoacetate (EDA), which give, in most cases, selectively 3‐hydroxyacrylates rather than β‐oxo esters. This reaction is strongly dependent on the nature of the counterion. Whereas with BF 4 – the reaction proceeds with conversions up to 90 %, in the case of the counterions NO 3 – , CF 3 COO – , CF 3 SO 3 – ,SbF 6 – , and BAr′ 4 – [Ar′ = 3,5‐(CF 3 ) 2 C 6 H 3 ] no reaction took place. In the case of PF 6 – only up to 20 % conversion was achieved. A conceivable mechanism for the coupling of aromatic aldehydes with EDA was established by means of DFT/B3LYP calculations, which allowed the rationalization of both the chemoselectivity and the role of the counterions.