Herein
is introduced the application of “super-electron-donor”(SED)
2-azaallyl anions in a tandem reduction/radical cyclization/radical
coupling/aromatization protocol that enables the rapid construction
of isoquinolines. The value of this transition-metal-free method is
highlighted by the wide range of isoquinoline ethyl amines prepared
with good functional group tolerance and yields. An operationally
simple gram scale synthesis is also conducted, confirming the scalability.
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.
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