Catalytic enantioselective construction of quaternary stereocenters by direct vinylogous Michael addition of deconjugated butenolides to nitroolefins.
نویسندگان
چکیده
A direct vinylogous Michael reaction of γ-substituted deconjugated butenolides with nitroolefins has been developed with the help of a newly identified quinine-derived bifunctional catalyst, allowing the synthesis of densely functionalized products with contiguous quaternary and tertiary stereocenters in excellent yield with perfect diastereoselectivity (>20:1 dr) and high enantioselectivity (up to 99:1 er).
منابع مشابه
Synergistic Lewis base and anion-binding catalysis for the enantioselective vinylogous addition of deconjugated butenolides to allenoates.
An enantioselective vinylogous umpolung addition of deconjugated butenolides to allenoates has been developed for the first time with the help of synergistic combination of an achiral phosphine and a chiral squaramide, and represents the first example of a catalytic enantioselective Cγ-Cγ bond formation between two different carbonyl partners.
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The diastereo- and enantioselective direct vinylogous Michael addition reaction of γ-substituted butenolides to 2-enoylpyridines has been achieved. A range of γ,γ-disubstituted butenolide derivatives, bearing two consecutive tri- and tetrasubstituted stereogenic centers, were readily obtained in good yields with excellent stereoselectivities (up to >99 : 1 dr and >99% ee).
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A highly enantioselective Michael addition reaction of 2-substituted benzofuran-3(2H)-ones to nitroolefins was promoted by a bifunctional squaramide catalyst. As a result, a number of chiral 2,2'-substituted benzofuran-3-one derivatives, bearing adjacent quaternary-tertiary stereocenters, were efficiently synthesized with excellent enantioselectivities.
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The first organocatalytic enantioselective direct vinylogous Michael reaction of α,β-unsaturated γ-butyrolactam to nitroolefins is developed using cinchona alkaloids as the catalysts. Both product enantiomers are accessible with moderate to good enantioselectivity.
متن کاملCatalytic Enantioselective Construction of All-Carbon Quaternary Stereocenters Catalytic Enantioselective Construction of All-Carbon Quaternary Stereocenters
SYNTHESIS 2006, No. 3, pp 0369–0396xx.xx.2006 Advanced online publication: 13.01.2006 DOI: 10.1055/s-2006-926302; Art ID: E14205SS © Georg Thieme Verlag Stuttgart · New York Abstract: Catalytic enantioselective construction of all-carbon quaternary stereocenters, i.e. carbon atoms bearing four different carbon substituents, poses a particular challenge in organic synthesis. This review gives a ...
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عنوان ژورنال:
- Chemical communications
دوره 51 80 شماره
صفحات -
تاریخ انتشار 2012