Premium
Divalent Samarium Triflate Mediated Stereoselective Pinacol Coupling of Planar Chiral Phosphanyl and Phosphoryl Ferrocenecarbaldehyde
Author(s) -
Fukuzawa Shinichi,
Oura Ichiro,
Shimizu Kenta,
Kato Minoru,
Ogata Kenichi
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.200801138
Subject(s) - chemistry , pinacol , trifluoromethanesulfonate , samarium , divalent , selectivity , diol , stereoselectivity , catalysis , medicinal chemistry , iodide , dihydroxylation , coupling reaction , organic chemistry , stereochemistry , enantioselective synthesis
The pinacol coupling reaction of ( Rp )‐2‐diphenylphosphanyl ferrocenecarbaldehyde ( 1 ) was smoothly mediated by divalent samarium triflate to give ( R , R )‐diol 2a predominantly, whereas the use of samarium(II) iodide resulted in low selectivity as described in the previous literature. In contrast, the coupling reaction of ( Rp )‐2‐diphenylphosphoryl ferrocenecarbaldehyde ( 3 ) with Sm(OTf) 2 gave the ( S , S )‐diol as the major isomer, which was the opposite stereochemistry of that obtained in the reaction with 1 . The rhodium complexes of diphosphanes 2a were good catalysts for the asymmetric hydrogenation of α‐acetamidocinnamic acid, and the product was obtained quantitatively with up to 92 % ee . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)