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Synfacts 2013; 9(1): 0109
DOI: 10.1055/s-0032-1317727
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart · New York

Asymmetric 1,4-Addition with a Chiral Calcium–Pybox Catalyst

Contributor(s):
Yasuhiro Uozumi
,
Yoichi M. A. Yamada
,
Aya Ohno
Tsubogo T, Yamashita Y, Kobayashi S * The University of Tokyo, Japan
Toward Efficient Asymmetric Carbon–Carbon Bond Formation: Continuous Flow with Chiral Heterogeneous Catalysts.

Chem. Eur. J. 2012;
18: 13624-13628
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Further Information

Publication History

Publication Date:
17 December 2012 (online)

 
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Key words

asymmetric catalysis - Michael addition - calcium - continuous-flow synthesis

Significance

A polymer-supported homochiral Pybox–calcium chloride complex catalyzed the asymmetric 1,4-addition of 1,3-dicarbonyl compounds 1 to nitroalkenes 2, to afford the corresponding adducts 3 in up to 98% yield and 95% ee under batch or flow conditions.


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Comment

The flow system worked for 204 hours without significant loss of catalytic activity to give 3a in 95.5% yield with 92.0% ee on average. The total amount of product was 291.4 mmol and the turn-over number (TON) reached 228.


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