Beilstein J. Org. Chem.2016,12, 429–443, doi:10.3762/bjoc.12.46
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Keywords: bifunctional; cupreidine; cinchona; cupreine; organocatalysis; Introduction
The cinchona alkaloids, comprising quinine (QN), quinidine (QD), cinchonidine (CD), cinchonine (CN, Figure 1), and their derivatives have revolutionized asymmetric catalysis owing to their privileged structures. The
optimize their stereoselective behaviour has seen their utility burgeon dramatically over the last decade. Of particular note is the use of these cinchona systems within bifunctional thiourea catalysis [3][4][5][6][7][8][9][10][11][12].
Cupreine (CPN) and cupreidine (CPD), the non-natural demethylated
set up a 4π-electrocyclization, generating second intermediate 27. Elimination of the tertiary amine then gives γ-methylene cyclopentenone 28.
1,2-Addition reactions
Henry reaction
The use of cupreine and cupreidine derivatives in the addition of nitroalkanes to carbonyl compounds was first
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Graphical Abstract
Figure 1:
The structural diversity of the cinchona alkaloids, along with cupreine, cupreidine, β-isoquinidine...