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Protected amino acids as a nonbonding source of chirality in induction of single-handed screw-sense to helical macromolecular catalysts.

ABSTRACT: Chiral nonbonding interaction with N-protected amino acid methyl esters used as chiral additives in achiral solvents allows dynamic induction of single-handed helical conformation in poly(quinoxaline-2,3-diyl)s (PQX) bearing only achiral substituents. Ac-l-Pro-OMe, for instance, allows induction of energy preference of 0.16 kJ mol^-1 per monomer unit for the M-helical structure over the P-helix in t-butyl methyl ether (MTBE). With this new mode of screw-sense induction, homochiral screw-sense has been induced in virtually achiral poly(quinoxaline-2,3-diyl)s 1000-mer containing phosphine pendants (PQXphos). Use of PQXphos as a helically dynamic ligand along with Ac-Pro-OMe (l or d) as a chiral additive in MTBE allowed a highly enantioselective Suzuki-Miyaura coupling reaction with up to 95% enantiomeric excess.

SUBMITTER: Ikeda S

PROVIDER: S-EPMC8246299 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature

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Protected amino acids as a nonbonding source of chirality in induction of single-handed screw-sense to helical macromolecular catalysts.

Ikeda Shoma S Takeda Ryohei R Fujie Takaya T Ariki Naoto N Nagata Yuuya Y Suginome Michinori M

Chemical science 20210526 25

Chiral nonbonding interaction with N-protected amino acid methyl esters used as chiral additives in achiral solvents allows dynamic induction of single-handed helical conformation in poly(quinoxaline-2,3-diyl)s (PQX) bearing only achiral substituents. Ac-l-Pro-OMe, for instance, allows induction of energy preference of 0.16 kJ mol-1 per monomer unit for the M-helical structure over the P-helix in t-butyl methyl ether (MTBE). With this new mode of screw-sens ...[more]

PMID: 34257881

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