Entrainer effects on enantiodifferentiating photocyclization of 5-hydroxy-1,1-diphenylpentene in near-critical and supercritical carbon dioxide

Yasuhiro Nishiyama, Takehiko Wada, Kiyomi Kakiuchi, Yoshihisa Inoue

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Enantiodifferentiating photocyclization of 5-hydroxy-1,1-diphenyl-1-pentene (1) sensitized by bis(1,2;4,5-di-O-isopropylidene-α-fructopyranosyl) 1,4-naphthalenedicarboxylate (2) was performed in near-critical and supercritical carbon dioxide media containing organic entrainers to obtain a chiral tetrahydrofuran derivative (3) in enantiomeric excess (ee) higher than those obtained in conventional organic solvents. Interestingly, the entrainer-driven ee enhancement did not depend on the entrainer polarity, which is in contrast to the behavior of the ee observed upon selective solvation in nonpolar organic solvents. This indicates that entrainer clustering around the intervening exciplex is essential in order to keep the intimate sensitizer-substrate contact within the exciplex. Therefore, the clustering itself, rather than its property, is more crucial to prevent the dissociative diffusion to gaseous CO 2. The wider allowance in choosing the entrainer enables us to use more "green" solvents for achieving the ee enhancement, while reducing the environmental risk.

Original languageEnglish
Pages (from-to)5681-5686
Number of pages6
JournalJournal of Organic Chemistry
Volume77
Issue number13
DOIs
Publication statusPublished - 2012 Jul 6

ASJC Scopus subject areas

  • Organic Chemistry

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