Open AccessConfigurationally homogeneous diastereomers of a linear hexa(tertiary phosphine): Enantioselective self-assembly of a double-stranded parallel helicate of the type ( P )-[Cu 3 (hexaphos) 2 ](PF 6 ) 3
Author(s) -
Paul K. Bowyer,
Ver C. Cook,
Nahid Gharib-Naseri,
Paul A. Gugger,
A. David Rae,
Gerhard F. Swiegers,
Anthony C. Willis,
Johann Zank,
S. Bruce Wild
Publication year - 2002
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.072640699
Subject(s) - diastereomer , stereocenter , chemistry , hexa , stereochemistry , enantiomer , ligand (biochemistry) , copper , phosphine , crystallography , metal , stereoselectivity , enantioselective synthesis , organic chemistry , receptor , biochemistry , catalysis
Three configurationally homogeneous diastereomers of the linear hexa(tertiary phosphine) Ph(2)PCH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)PPh(2) (hexaphos) have been isolated in enantiomerically pure form, namely (R,S,S,R)-, (R,S,S,S)-, and (S,S,S,S)-hexaphos. The strongly helicating (R,S,S,R)-(-) form of the ligand combines with copper(I) ions to generate by stereoselective self-assembly the P enantiomer of a parallel helicate of the type [Cu(3)(hexaphos)(2)](PF(6))(3), which has been characterized by x-ray crystallography. Theoretical modeling of the cation indicates that it is the relationship between the helicities of the two 10-membered rings containing the three copper ions, each of which has the twist-boat-chair-boat conformation, and the configurations of the three chiral, tetrahedral copper stereocenters of P configuration that determines the stereochemistry of the parallel and double alpha-helix conformers of the double-stranded trinuclear metal helicate.