Allenyl Azide Cycloaddition Chemistry. 2,3-Cyclopentennelated Indole Synthesis through Indolidene Intermediates
摘要:
The thermal, photochemical, and photochemical/CuI-mediated cascade cyclizations of a range of substituted 1-(2-azidophenyl)-3-alkenylallenes are described. These reactions provide both 1,2- and 2,3-cyclopentennelated indole products in varying ratios. In most cases, high regioselectivity for the 2,3-annelated isomer can be achieved under the hv/CuI conditions. Computational studies of this multistep reaction support the intermediacy of indolidene intermediates whose electrocyclizations (with or without copper present) define the regioselectivity branch point in the sequence.
Allenyl Azide Cycloaddition Chemistry. Synthesis of Annelated Indoles from 2-(Allenyl)phenyl Azide Substrates
摘要:
[GRAPHICS]Thermolysis of 2-(allenyl) phenyl azides leads to a cascade cyclization sequence furnishing both C(2)-C(3) and N-C(2) cyclopentannelated indoles.