Tandem Functionalization of Nonactivated Alkenes and Alkynes in Intramolecular <i>N</i>-Acyloxyiminium Ion Carbocyclization. Synthesis of 6-Substituted Hydroindole 2-Carboxylic Acids
作者:Stephen Hanessian、Martin Tremblay
DOI:10.1021/ol040053b
日期:2004.12.1
[reaction: see text] Five-membered N-Boc acyliminium ions derived from L-pyroglutamic acid harboring 4-butenyl and 4-butynyl tethers undergo Lewis acid-mediated halo and tandem Friedel-Crafts carbocyclization within minutes at -78 degrees C to give stereodefined 6-substituted octahydroindole and hexahydroindole 2-carboxylic acid methyl esters, respectively. The cyclic vinyl bromides are excellent substrates