Pseudoenantiomeric cinchonidine

The pseudoenantiomeric catalysts derived from the alkaloid pairs cinchonine/cinchonidine and quinidine/quinine (1/4 or 2/5, respectively) are related as diastereomers but are enantiomeric with respect to the front working-face defined by carbons 8 and 9. 

The effect of the nature of the cinchona alkaloid component was then investigated (Scheme 4.4). The cinchonine-derived PTC 9, which are in pseudoenantiomeric relationship to the cinchonidine-derived compound 7, produced the opposite... 

As mentioned in the previous section, nowadays, readily available and inexpensive cinchona alkaloids with pseudoenantiomeric forms, such as quinine and quinidine or cinchonine and cinchonidine, are among the most privileged chirality inducers in the area of asymmetric catalysis. The key feature responsible for their successful utility in catalysis is that they possess diverse chiral skeletons and are easily tunable for diverse types of reactions (Figure 1.2). The presence of the 1,2-aminoalcohol subunit containing the highly basic and bulky quinuclidine, which complements the proximal Lewis acidic hydroxyl function, is primarily responsible for their catalytic activity. 

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