Enantioselective synthesis of 4H-pyranonaphthoquinones via sequential squaramide and silver catalysis.
نویسندگان
چکیده
An enantioselective one-pot Michael addition/hydroalkoxylation reaction between 2-hydroxy-1,4-naphthoquinones and alkyne-tethered nitroalkenes catalyzed by a cinchona-derived squaramide and a silver(I) salt has been developed. The sequential protocol provides a direct access to 4H-pyranonaphthoquinones in moderate to very good yields and good to excellent enantioselectivities at a very low catalyst loading (0.5 mol%) of the squaramide.
منابع مشابه
Highly enantioselective synthesis of naphthoquinones and pyranonaphthoquinones catalyzed by bifunctional chiral bis-squaramides.
A variety of enantioenriched naphthoquinones have been synthesized in high yields and excellent enantioselectivities (up to >99% ee) using a bifunctional chiral bis-squaramide catalyzed conjugate addition of 2-hydroxy-1,4-naphthoquinone to 2-enoylpyridines. Some of the Michael products have been successfully converted into various enantioenriched pyranonaphthoquinone derivatives. The protocol i...
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ورودعنوان ژورنال:
- Chemical communications
دوره 52 8 شماره
صفحات -
تاریخ انتشار 2016