Synthesis of Tryptamines from Radical Cyclization of 2-Iodoaryl Allenyl Amines and Coupling with 2-Azallyls

An efficient synthesis of tryptamines is developed. Indole structures were constructed using 2-iodoaryl allenyl amines as electron acceptors and radical cyclization precursors. Radical-radical coupling of indolyl methyl radicals and azaallyl radicals led to the tryptamine derivatives. The utility and versatility of this method are showcased by the synthesis of 22 examples of tryptamines in <= 88% yield. In each case, indole formation is accompanied by in situ removal of the Boc protecting group.

Automated summary

An efficient synthesis method for tryptamines has been developed using 2-iodoaryl allenyl amines and radical cyclization reactions to construct indole structures. The utility and versatility of this method are demonstrated by the successful synthesis of 22 tryptamine derivatives in high yields. The formation of indoles is accompanied by the in situ removal of the Boc protecting group.