Organic Letters
Letter
To illustrate the utility of our enantioselective cyclization of
α,β-unsaturated carbonyl diazoacetates, we prepared key
intermediates in the reported synthesis of DCG-IV10 and
dysibetaine CPa11 from the cyclopropane-fused γ-lactone 2a
(Scheme 1). DCG-IV is a (dicarboxycyclopropyl)glycine that is
enantioselectivity (ee up to 99%). This method enables efficient
access to enantioenriched dicarbonyl cyclopropane derivatives,
which are important building blocks for the synthesis of
pharmaceuticals and natural products.
ASSOCIATED CONTENT
* Supporting Information
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Scheme 1. Preparation of Key Intermediates for the
Synthesis of Bioactive Compounds
S
Experimental procedures and characterization of the products.
The Supporting Information is available free of charge on the
AUTHOR INFORMATION
Corresponding Authors
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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This work was supported by a Grant-in-Aid for Scientific
Research (B) (No. 26288087) from Japan Society for the
Promotion of Science.
REFERENCES
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known to be an anticonvulsant agent, being a potent group II
mGluR agonist with neuroprotective properties, and is also
active as an agonist at the NMDA receptor. The shortest
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the α,β-unsaturated carbonyl diazoacetate 1a, which gives the
chiral cyclopropane-fused γ-lactone 2a. A subsequent ring
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To summarize, we have established a highly enantioselective
intramolecular cyclopropanation of electron-deficient olefins.
The use of the Ru(II)−Pheox complex as a catalyst was found
to be crucial to the reaction and gave the chiral cyclopropane-
fused γ-lactones in high yield (up to 99%) with excellent
C
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