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Spiroketal‐Based Phosphorus Ligands for Highly Regioselective Hydroformylation of Terminal and Internal Olefins
Author(s) -
Jia Xiaofei,
Wang Zheng,
Xia Chungu,
Ding Kuiling
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201203042
Subject(s) - hydroformylation , regioselectivity , chemistry , rhodium , ligand (biochemistry) , catalysis , denticity , isomerization , phosphoramidite , medicinal chemistry , organic chemistry , stereochemistry , crystal structure , dna , biochemistry , receptor , oligonucleotide
Abstract A new class of bidentate phosphoramidite ligands, based on a spiroketal backbone, has been developed for the rhodium‐catalyzed hydroformylation reactions. A range of short‐ and long‐chain olefins, were found amenable to the protocol, affording high catalytic activity and excellent regioselectivity for the linear aldehydes. Under the optimized reaction conditions, a turnover number (TON) of up to 2.3×10 4 and linear to branched ratio ( l/b ) of up to 174.4 were obtained in the Rh I ‐catalyzed hydroformylation of terminal olefins. Remarkably, the catalysts were also found to be efficient in the isomerization–hydroformylation of some internal olefins, to regioselectively afford the linear aldehydes with TON values of up to 2.0×10 4 and l/b ratios in the range of 23.4–30.6. X‐ray crystallographic analysis revealed the cis coordination of the ligand in the precatalyst [Rh( 3 d )(acac)], whereas NMR and IR studies on the catalytically active hydride complex [HRh(CO) 2 ( 3 d )] suggested an eq–eq coordination of the ligand in the species.