Highly enantioselective and diastereoselective cycloaddition of cyclopropanes with nitrones and its application in the kinetic resolution of 2-substituted cyclopropane-1,1-dicarboxylates.
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چکیده
منابع مشابه
Synthesis of 2,4,5-trisubstituted oxazoles through tin(IV) chloride-mediated reaction of trans-2-aryl-3-nitro-cyclopropane-1,1-dicarboxylates with nitriles.
trans-2-Aryl-3-nitro-cyclopropane-1,1-dicarboxylates when reacted with nitriles in the presence of tin(IV) chloride afford 2,4,5-trisubstituted oxazoles in good to excellent yields. The reactions take place through in situ generation of aroylmethylidene malonates from the cyclopropanes, followed by conjugate addition of nitriles to the malonates to form nitrilium ion intermediates and subsequen...
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Trifluoromethylated organic compounds, especially chiral quaternary alcohols bearing trifluoromethyl group are of important intermediates in drugs, agrochemicals and etc.An efficient epoxidation of β-CF3-β,β-disubstituted unsaturated ketones (6) has been developed with environmental benign hydrogen peroxide as the oxidant and F5-substituted chiral qua...
متن کاملA homo [3+2] dipolar cycloaddition: the reaction of nitrones with cyclopropanes.
Cycloadditions are among the most trusted of chemical transformations available to the synthetic chemist. The predictability of the transition state based on steric and electronic considerations allows for the strategic construction of complex molecular assemblies. While the Diels–Alder reaction has received the most attention, 1,3-dipolar cycloadditions have also maintained a place of prominen...
متن کاملYb(NTf2)3-catalyzed [3 + 3] cycloaddition between isatin ketonitrones and cyclopropanes to construct novel spiro[tetrahydro-1,2-oxazine]oxindoles.
Yb(NTf(2))(3)-catalyzed [3 + 3] cycloaddition between isatin ketonitrones and cyclopropanes is described. A variety of spiro[tetrahydro-1,2-oxazine]oxindoles were obtained in moderate to good yields along with good regioselectivities. This is the first example of the intermolecular [3 + 3] cycloaddition between ketone-derived nitrones and cyclopropanes.
متن کامل1,3-Dipolar [3 + 2] cycloaddition reactions of N,C,C-trisubstituted nitrones with ring-acceptor methylenecyclopropanes: a computational study
BACKGROUND 1,3-Dipolar [3 + 2]-cycloaddition of nitrones to the carbon-carbon double bonds of methylenecyclopropanes yields a mixture of regioisomeric 4- and 5-isoxazolidines. The mechanisms of the reactions of N,C,C-trisubstituted nitrones with ring acceptor substituted dimethyl methylenecyclopropanes-1,2-dicarboxylate and aryl methylidene cyclopropanes-1,1-dicarboxylate have been investigated...
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عنوان ژورنال:
- Angewandte Chemie
دوره 46 21 شماره
صفحات -
تاریخ انتشار 2007