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Due to its unique electronic properties, the difluoromethylene group (CF 2) has served as a valuable unity in the design of biologically active molecules. Since γ-lactones display a broad range of biological properties, α,α-difluoro-γ-lactones may exhibit unexpected biological activities, and thus their synthesis has received increasing attention. Traditional synthetic methods suffer from tedious multi-step processes, and very few effective methods have been reported recently. Herein, we describe the difunctionalization of alkenes with BrCF2CO2K under photoredox catalysis with the use of a boron-Lewis acid for the access to α,α-difluoro-γ-lactones. In this transformation, the alkene substrates and the used reagents, including BrCF2CO2K and the boron-Lewis acid, PhB(OH) 2 or BF3• THF, are cheap and widely available. High efficiency and atom economy may make this protocol attractive. [ABSTRACT FROM AUTHOR]

This paper proposes a novel data hiding method for JPEG 2000 coded images that embed multi-level information into quantized discrete wavelet transformed coefficients. Since the proposed method hides information represented as an integer to a transformed coefficient rounded to an integer, a JPEG 2000 code-stream conveying data keeps its standard JPEG 2000 code-stream structure. The proposed method is able to extract hidden data without memorizing embedding positions; it thus chooses transformed coefficients to which data is hidden freely. This characteristic makes the proposed method suitable for hiding data to a JPEG 2000 coded image with consideration of Region of Interest (ROI) coding that is a major feature. Simulation results show the effectiveness of the proposed method. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(7): 37– 46, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20286 [ABSTRACT FROM AUTHOR]