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Enantiomerically Pure Poly(oxymethylene) Helices: Correlating Helicity with Centrochirality
Author(s) -
Eppacher Simon,
Giester Gerald,
Bats Jan W.,
Noe Christian R.
Publication year - 2008
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200890062
Subject(s) - chemistry , pentamer , stereocenter , dimer , chirality (physics) , tetramer , foldamer , diastereomer , stereochemistry , crystallography , absolute configuration , helicity , helix (gastropod) , organic chemistry , enantioselective synthesis , ecology , biochemistry , chiral symmetry breaking , physics , particle physics , quantum mechanics , quark , snail , nambu–jona lasinio model , biology , enzyme , catalysis
A first series of enantiomerically pure helical oligo(formaldehyde)s (=oligo(oxymethylen)s) 16 – 20 was synthesized. To induce the chiral uniformity of the helices, we used (1 S )‐2,2‐dimethyl‐1‐phenylpropan‐1‐ol ( 14 ) to generate the end groups at the α and ω terminus ( Scheme 6 ). Propanol 14 was accessible from its racemate by acetal formation with lactol 12 and separation of the diastereoisomers ( Scheme 5 ). The helicity of the oligomers was investigated by temperature‐dependent CD, NMR, and optical‐rotation studies. In addition to qualitative considerations concerning the helicity of oligo(formaldehyde)s, we performed calculations of the dimer 17 and the pentamer 20 as well as X‐ray structure analyses of the dimer 17 and the tetramer 19 to establish the handedness of the helices and to correlate their sense with the absolute configuration of the inducing stereogenic center. The results may be of relevance with respect to induction and propagation of chirality in prebiotic chemistry.