Allenyl azide cycloaddition chemistry. 2,3-cyclopentennelated indole synthesis through indolidene intermediates.
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.
Feldman
Ken S
KS
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA. ksf@chem.psu.edu
Hester
D Keith
DK
Iyer
Malliga R
MR
Munson
Paul J
PJ
Silva López
Carlos
C
Faza
Olalla Nieto
ON
D001386:Azides / Q000737:chemistry*; D003198:Computer Simulation; D003300:Copper / Q000737:chemistry; D003500:Cyclization; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D008027:Light; D015394:Molecular Structure; D013237:Stereoisomerism; D013816:Thermodynamics
D001386:Azides; D007211:Indoles; D003300:Copper