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Synfacts 2010(10): 1199-1199  
DOI: 10.1055/s-0030-1258661
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart ˙ New York

Flow Ozonolysis Using a Semipermeable Teflon AF-2400 Membrane

Contributor(s):Yasuhiro Uozumi, Yoichi M. A. Yamada, Maki Minakawa
M. O’Brien, I. R. Baxendale, S. V. Ley*
University of Cambridge, UK
Flow Ozonolysis Using a Semipermeable Teflon AF-2400 Membrane to Effect Gas-Liquid Contact
Org. Lett.  2010,  12:  1596-1598  
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Publication History

Publication Date:
22 September 2010 (online)

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Key words

ozonolysis - semipermeable membranes - Teflon AF-2400 - flow chemistry

Significance

A simple and convenient flow chemistry device to bring about the ozonolysis of exomethylenes via gas-to-liquid transfer through semipermeable Teflon AF-2400 tubing was ­developed. Using a Teflon AF-2400 tubing (90 cm length) connected to a syringe pump (Infors AG, HT-Precidor), the flow ozonolysis of a series of ­exomethylenes was carried out in methanol with one hour of residence time to give the corresponding ketones (10 examples, 73-95% yield). A citronellol derivative (C10-OTBS) was converted into a C7-OTBS aldehyde under similar conditions in 57% yield.

Comment

Gas-liquid contact in a flow chemistry device usually involves the mechanical mixing of two phases. Here, more efficient, controllable, and reliable phase contact was realized using a semipermeable membrane that had high surface areas and selectively allowed O3 to cross from outside to inside. Telfon AF-2400 consists of an amorphous copolymer of tetrafluoroethylene and a ­perfluorodimethyldioxolane.

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