N-Fluorenyltryptamines as a Useful Platform for Catalytic Enantio-selective Pictet-Spengler Reactions

In the presence of a thiourea-carboxylic acid catalyst, N-9-fluorenyltryptamines undergo highly enantioselective Pictet-Spengler reactions with a range of aldehydes. The reaction works particularly well with aromatic aldehydes, tolerating electronically diverse substituents in all ring positions. Electron-deficient tryptamines are viable substrates. Removal of the fluorenyl protecting group is readily accomplished without deterioration of product ee.

Automated summary

In the presence of a thiourea-carboxylic acid catalyst, N-9-fluorenyltryptamines undergo highly enantioselective Pictet-Spengler reactions with a range of aldehydes. The reaction exhibits good compatibility with aromatic aldehydes, accepting diverse substituents at various positions on the ring. Electron-deficient tryptamines can also be used as substrates. Furthermore, the fluorenyl protecting group can be easily removed without affecting the enantioselectivity of the product.