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Enantioselective Michael Addition Reaction Catalysed by Enantiopure Binuclear Nickel(II) Close‐Ended Helicates
Author(s) -
Chinnaraja Eswaran,
Arunachalam Rajendran,
Samanta Krishanu,
Natarajan Ramalingam,
Subramanian Palani S.
Publication year - 2020
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.201901350
Subject(s) - enantiopure drug , chirality (physics) , chemistry , enantioselective synthesis , enantiomer , nickel , catalysis , stereochemistry , ligand (biochemistry) , diamine , phenol , yield (engineering) , medicinal chemistry , organic chemistry , physics , biochemistry , chiral symmetry breaking , receptor , quantum mechanics , quark , nambu–jona lasinio model , thermodynamics
The enantiopure Ni(II) helicates [Ni 2 L 1 RR .Cl 2 ] ( 1 ), [Ni 2 L 1 SS .Cl 2 ] ( 1′ ), [Ni 2 L 2 RR .Cl 2 ] ( 2 ), [Ni 2 L 2 SS .Cl 2 ] ( 2′ ) were synthesized by one‐pot self‐assembly technique from R ‐(+)‐ or S ‐(−)‐1,1′‐binaphthyl‐2,2′‐diamine, with 4‐methyl‐2,6‐diformyl phenol or 4‐ tert ‐butyl‐2,6‐diformyl phenol and nickel salts. This binuclear double stranded Ni(II) helicates were characterized by ESI‐MS, IR and single crystal X‐ray structure wherever applicable. The extensive chiroptical studies suggest that the complexes are enantiopure in nature. The chirality transfer from ligand L 1RR & L 2RR to Ni(II) metal centre produced ΔΔ geometrical chirality, while their enantiomeric counterpart L 1SS & L 2SS produced ΛΛ chirality in their respective complexes.These enantiopure helicates were applied as catalysts in asymmetric Michael addition of 1,3‐dicarbonyl compounds with β‐nitrostyrene to produce nitroalkanes in good yield (96–98%) and ee (78–94%).