title: Chiral recognition of cyclic alpha-hydroxyketones by CD-sensitive zinc tetraphenylporphyrin tweezer.
abstract: A combined chemical/chiroptical microscale protocol for the determination of absolute configurations of cyclic alpha-hydroxyketones is described. The hydroxyl group in cyclic alpha-hydroxyketones is converted into (3-aminopropylamino)acetate (NH2CH2CH2CH2NHCH2COOR), or more generally, according to a newly developed protocol, into (3-hydroxypropylamino)acetate group (HOCH2CH2CH2NHCH2COOR). The resultant conjugated compound forms a 1:1 host-guest complex with a dimeric zinc porphyrin tweezer, which exhibits exciton-coupled bisignate CD spectrum centered around the 420-nm porphyrin Soret band due to induced helicity between the two porphyrins in the complex. The absolute configurations of the alpha-stereogenic center is then determined by comparison of the sign of the observed CD exciton couplet of the complex with that of the preferred porphyrin twist predicted by the Merck Molecular Force Field (MMFFs) method.
authors.affiliation: Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA.
authors.forename: Hideki
authors.initials: H
authors.lastname: Ishii
authors.forename: Yihui
authors.initials: Y
authors.lastname: Chen
authors.forename: Ross A
authors.initials: RA
authors.lastname: Miller
authors.forename: Sandor
authors.initials: S
authors.lastname: Karady
authors.forename: Koji
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Nina
authors.initials: N
authors.lastname: Berova
mesh_terms: D002942:Circular Dichroism; D007659:Ketones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008665:Metalloporphyrins; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013237:Stereoisomerism
chemical_list: D007659:Ketones; D008665:Metalloporphyrins; C048955:zinc tetraphenylporphyrin