Enantioselective cyclization of racemic supramolecular polymers.
Homochiral hydrogen-bonded cyclic assemblies are formed in dilute solutions of racemic supramolecular polymers based on the quadruple hydrogen bonding 2-ureido-4[1H]-pyrimidinone unit, as observed by 1H NMR and SEC experiments. Preorganization of the monomers and the combined binding strength of the eight hydrogen bonds result in a very high stability of the cyclic aggregates with pronounced selectivity between homochiral and heterochiral cyclic species, usually only observed in crystalline or liquid crystalline phases.
ten Cate
A Tessa
AT
Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Dankers
Patricia Y W
PY
Kooijman
Huub
H
Spek
Anthony L
AL
Sijbesma
Rint P
RP
Meijer
E W
EW
D003500:Cyclization; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D011744:Pyrimidinones / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
D011108:Polymers; D011744:Pyrimidinones