2024-03-29T13:48:05Z
https://nagoya.repo.nii.ac.jp/oai
oai:nagoya.repo.nii.ac.jp:02002065
2023-01-16T05:07:58Z
320:321:322
Emergence of Highly Enantioselective Catalytic Activity in a Helical Polymer Mediated by Deracemization of Racemic Pendants
Ikai, Tomoyuki
Ando, Mitsuka
Ito, Masaki
Ishidate, Ryoma
Suzuki, Nozomu
Maeda, Katsuhiro
Yashima, Eiji
Any polymers composed of racemic repeating units are obviously optically inactive and hence chiral functions, such as asymmetric catalysis, will not be expected at all. Contrary to such a preconceived notion, we report an unprecedented helical polymer-based highly enantioselective organocatalyst prepared by polymerization of a racemic monomer with no catalytic activity. Both the right- and left-handed helical poly(biarylylacetylene)s (PBAs) composed of dynamically racemic 2-arylpyridyl-N-oxide monomer units with N-oxide moieties located in the vicinity of the helical polymer backbone can be produced by noncovalent interaction with a chiral alcohol through deracemization of the biaryl pendants. The macromolecular helicity and the axial chirality induced in the PBAs are retained (“memorized”) after complete removal of the chiral alcohol. Accordingly, the helical PBAs with dual static memory of the helicity and axial chirality show remarkable enantioselectivity (86% ee) for the asymmetric allylation of benzaldehyde. The enantioselectivity is slightly lower than that (96% ee) of the homochiral PBAs prepared from the corresponding enantiopure (R)- and (S)-monomers, but is comparable to that (88% ee) of the helical PBA composed of nonracemic monomers of ca. 60% ee.
journal article
ACS Publications
2021-08-18
application/pdf
Journal of the American Chemical Society
32
143
12725
12735
0002-7863
https://nagoya.repo.nii.ac.jp/record/2002065/files/Ikai-rev.pdf
eng
https://doi.org/10.1021/jacs.1c05620
This document is the Accepted Manuscript version of a Published Work that appeared in final form in [Journal of the American Chemical Society], copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see [https://pubs.acs.org/articlesonrequest/AOR-IPYDMMW32CQUCQHQMZBX].”