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Rhodium versus Iridium Catalysts in the Controlled Tandem Hydroformylation–Isomerization of Functionalized Unsaturated Fatty Substrates
Author(s) -
Ternel Jérémy,
Couturier JeanLuc,
Dubois JeanLuc,
Carpentier JeanFrançois
Publication year - 2015
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201402783
Subject(s) - hydroformylation , rhodium , iridium , isomerization , catalysis , chemistry , ruthenium , olefin fiber , ligand (biochemistry) , palladium , aldehyde , medicinal chemistry , photochemistry , organic chemistry , biochemistry , receptor
The hydroformylation of 10‐undecenitrile ( 1 ) and related unsaturated fatty substrates (H 2 CCH(CH 2 ) 7 CH 2 R; R=CO 2 Me, CH 2 Br, CHO) has been studied with rhodium, iridium, ruthenium, and palladium biphephos catalysts. The reactions proceeded effectively with all four systems, with high selectivities for the linear aldehyde (ratio of linear/branched aldehydes=99:1). The biphephos‐bis[chloro(cyclooctadiene)iridium] system showed a non‐optimized hydroformylation turnover frequency (TOF HF ) of 770 h −1 that was only approximately 5 times lower than that of the rhodium‐based system (TOF HF =3320 h −1 ); the palladium and ruthenium biphephos systems were less active (TOF HF =210 and 310 h −1 , respectively). Upon recycling, remarkable productivities were achieved in both cases (TON≈58 000 mol( 1 / 1‐ int ) mol(Ir) −1 and 250 000 mol( 1 / 1‐ int ) mol(Rh) −1 , in which int =internal olefin). Competitive isomerization of terminal to internal olefins occurred with these catalysts. Iridium biphephos systems allowed slightly better control of the distribution of the internal isomers than the rhodium biphephos catalyst, with higher ratios of 9‐/8‐undecenitrile ( 1‐ int ).