Practical Stereoselective Synthesis of C3-Spirooxindole- and C2-Spiropseudoindoxyl-Pyrrolidines via Organocatalyzed Pictet-Spengler Reaction/Oxidative Rearrangement Sequence

A stereoselective synthetic route to chiral C3-spirooxindole- and C2-spiropseudoindoxyl-pyrrolidines was accomplished by an enantioselective organocatalyzed Pictet-Spengler reaction of tryptamines and isotryptamines followed by a diastereoselective oxidative rearrangement using eco-friendly oxidants (i. e., NaOCl . 5H(2)O and Oxone (R)). This sequential reaction enables rapid access to chiral C3-spirooxindole- and C2-spiropseudoindoxyl-pyrrolidines in a one-pot process. A Wnt signaling inhibitory assay of the prepared enantioenriched spiro compounds demonstrated that they exhibited moderate activities.

Automated summary

A stereoselective synthetic route to chiral C3-spirooxindole- and C2-spiropseudoindoxyl-pyrrolidines was successfully achieved by an enantioselective organocatalyzed Pictet-Spengler reaction followed by a diastereoselective oxidative rearrangement. The prepared enantioenriched spiro compounds demonstrated moderate activities in a Wnt signaling inhibitory assay. Eco-friendly oxidants were used in the process, enabling rapid access to the chiral compounds.