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 hnu/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.
The thermal, photochemical, and photochemn class="Chemical">ical/CuI-mediated cascade cyclizations of a range of substituted 1-(2-azidophenyl)-3-alkenylallenesare 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 hnu/CuI conditions. Computational studies of this multistep reaction support the intermediacy of indolideneintermediates whose electrocyclizations (with or without copper present) define the regioselectivity branch point in the sequence.
Authors: Carlos Silva López; Olalla Nieto Faza; Ken S Feldman; Malliga R Iyer; D Keith Hester Ii Journal: J Am Chem Soc Date: 2007-05-27 Impact factor: 15.419