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Effective Guest Inclusion by a 6-O-Modified β-Cyclodextrin Dimer in Organic Solvents

Chizuru Asahara, Takuya Iwamoto, Mitsuru Akashi, Hajime Shigemitsu, Toshiyuki Kida

Chempluschem. 2018 Sep;83(9):868-873.

PMID: 31950682

Abstract:

A 6-O-tert-butyldimethylsilylated β-cyclodextrin (TBDMS-β-CD) dimer, in which two TBDMS-β-CD rings are connected in a head-to-head fashion by a m-xylylene linker, effectively forms inclusion complexes with pyrene and naphthalene in nonpolar organic solvents such as cyclohexane and benzene. This TBDMS-β-CD dimer shows a higher inclusion ability toward these guests than a TBDMS-β-CD dimer bearing a p-xylylene linker due to the greater cooperation of the two TBDMS-β-CD rings for the guest inclusion. Unlike the corresponding monomer, the TBDMS-β-CD dimer bearing a m-xylylene linker is also a good host even in polar organic solvents such as tetrahydrofuran. High chiral recognition of aromatic amines and alcohol is realized by utilizing inclusion within the cavity of the TBDMS-β-CD dimer in cyclohexane. In particular, an extremely high binding selectivity for (S)-1-(1-naphthyl)ethylamine and (S)-1-(1-naphthyl)ethanol over the corresponding (R)-isomers is achieved. Moreover, by utilizing the high chiral recognition with the TBDMS-β-CD dimer in cyclohexane, a non-enzymatic kinetic resolution of racemic 1-(1-naphthyl)ethylamine via enantioselective N-benzoylation is attained with an enantiomer excess of up to 87 % and an s-factor of 15.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP10420890 (S)-(−)-1-(1-Naphthyl)ethylamine (S)-(−)-1-(1-Naphthyl)ethylamine 10420-89-0 Price
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