Enantioselective decarboxylative protonation synthesis

The enantioselective decarboxylative protonation, which is directly related to the venerable malonic add synthesis, has not shown the major advances in terms of selectivity that we could have expected for the oldest methodology used to carry out enantioselective protonations (Marckwald, 1904). The use of this reaction and, in particular, of its organocatalyzed version for the synthesis of compounds of biological significance is now emerging. This highlights the synthetic potential of this low-cost and operationally simple reaction, notably in the context of sustainable chemistry. However, this asymmetric reaction is not yet mature. Further investigations... 

The isoflavanone precursors 8a-e were then applied in the decarboxylative asymmetric protonation reaction. Recently Pd-catalysed decarboxylative reactions have emerged as a powerful tool in organic synthesis (see Sects. 4.3 and 4.4) [32, 33]. The often mild reaction conditions employed, coupled with the high yields and enantioselectivities attainable has seen this methodology applied in several syntheses [34—37] and continues to be an area of rapid growth in asymmetric catalysis. 

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