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An Effective Dual Copper‐ and Sulfide‐Catalytic System for the Epoxidation of Aldehydes with Phenyldiazomethane
Author(s) -
Pereira Ana,
Martín Carmen,
Maya Celia,
Belderrain Tomás R.,
Pérez Pedro J.
Publication year - 2013
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201300606
Subject(s) - chemistry , tetrahydrothiophene , catalysis , tetrahydrofuran , ligand (biochemistry) , copper , acetonitrile , sulfide , adduct , benzaldehyde , solvent , medicinal chemistry , inorganic chemistry , organic chemistry , biochemistry , receptor
Epoxides have been obtained from aldehydes and phenyldiazomethane using catalytic amounts of both the copper homoscorpionate complexes Tp x CuL (Tp x =homoscorpionate ligand; L=acetonitrile or tetrahydrofuran, THF) and dimethyl sulfide (SMe 2 ) in high yields and diasteroselectivities, and with activities higher (TOF=46 h −1 ) than those already known with rhodium‐ or copper‐based catalysts. Among the copper(I) homoscorpionate complexes tested, Tp Br3 Cu(NCCH 3 ) showed the highest catalytic activity under mild conditions. The catalytic activity is controlled by electronic effects induced by the Tp x ligand as well as by the stability of the Tp x Cu(SR 2 ) adducts. Indeed, in the case of Tp Ms as ligand, the Tp Ms Cu(THT) (THT=tetrahydrothiophene) and Tp Ms Cu(SMe 2 ) species could be isolated as very stable crystalline solids, the molecular structure of the former being confirmed by single‐crystal X‐ray diffraction analysis. The in situ generation of PhCHN 2 from benzaldehyde tosylhydrazone sodium salt at 60 °C in methyl tert ‐butyl ether as solvent and Tp Ms Cu(THF) as the catalyst also showed high catalytic activities, improving those already reported with copper‐based catalysts.