ChemInform Abstract: Synthetic Approaches to gem‐Difluoromethylene Compounds

Abstract

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Synthesis of Novel Angular Spirocyclic Azetidines

“…In contrast, angular frameworks have only been described by our group . Because we anticipate wide potential for the use of scaffold 4 in medicinal chemistry, we envisaged extending the profile of 4 by incorporation of a variety of substituents on the underlying scaffold, such as gem -difluoro and -dimethyl groups by virtue of their frequency of use in medicinal chemistry. , We wish to report the syntheses of novel angular 3,3- and 2,2- gem -disubstituted 1,6-diazaspiro[3.3]heptanes 5 and 6 , as well as 5-oxo-2-azaspiro[3.3]heptane 7 and derivatives 8 of the underlying scaffold. These are derived from a common precursor azetidin-3-one.…”

CuBr-Catalyzed Oxidative Difluoromethylation of Tertiary Amines with Difluoroenol Silyl Ethers

“…The introduction of one or a few fluorine atoms into an organic molecule produces profound changes in its chemical, physical, and pharmacological properties . Especially, incorporation of a gem -difluoromethylene group (CF 2 ) into an organic molecule has been used as a strategy for modification of biologically active compounds . This is because the difluoromethylene group can not only enhance its neighboring group acidity but also significantly improve its biological stability when an oxygen at a biochemically labile position is replaced with a CF 2 group.…”

Highly Diastereoselective Zn/SnCl2-Mediated gem-Difluoroallylation of Chiral Hydrazones

“…Fluorinated compounds play a very important role in life sciences due to the introduction of one or a few fluorine atoms into an organic molecule showing profound changes in its chemical and biological nature . Among them, gem -difluorinated molecules constitute a distinct class of fluorinated compounds . Incorporation of a gem -difluoromethylene group (CF 2 ) into an organic molecule can not only enhance its neighboring group stability or acidity but also act as an isopolar−isosteric substitute for oxygen .…”

“…It has been used as one strategy for modification of biologically active compounds, such as enzyme inhibitors, and anticancer agents (e.g., Gemcitabine and Vinflunine have been extensively used for treatment of lung, ovarian, renal, pancreatic, head and, neck cancers). Therefore, many efforts have been focused on the synthesis of gem -difluorinated compounds. , The most commonly used methods thus far are direct difluorination of carbonyl with DAST and the Reformatsky reaction using bromodifluoroacetate . However, to incorporate a gem -difluoromethylene group to an organic molecule in a chemo- , regio- , and stereo- manner is still a great challenge …”