Journal of the American Chemical Society, Vol.136, No.43, 15138-15141, 2014
Intramolecular [3+2] Cyclocondensations of Alkenes with Indolidenes and Indolidenium Cations
C(2)-C(3) cyclopentannelated indole constructs are prepared by either (a) a cyclization cascade of an alkenyl sulfide tethered to a 2-azido-1-allenylbenzene core or (b) cationic cyclization of a tethered alkenyl sulfide with a putative 2-indolidenium cation. In both cases, issues of C-C versus C-N bond formation emerge, and the results indicate that the former is favored.