Journal of the American Chemical Society, Vol.129, No.31, 9631-9634, 2007
C-2/C-3 annulation and C-2 alkylation of indoles with 2-alkoxycyclopropanoate esters
The annulation reaction between various indoles and 2-alkoxycyclopropanoate esters is reported. Both high efficiency and complete stereochemical control were observed in some cases with this annulation process. A single stereocenter on the cyclopropane controls the diastereoselective formation of up to four new stereocenters. A different reaction course was observed with 3-substituted indole substrates, and an intervening C-3 to C-2-migration process arose that gives synthetically useful C-2 alkylation indole products.