- PPA-mediated C-C bond formation: a synthetic route to substituted indeno[2,1-c]quinolin-6(7H)-ones.
PPA-mediated C-C bond formation: a synthetic route to substituted indeno[2,1-c]quinolin-6(7H)-ones.
Organic letters (2013-02-09)
Xu Liu, Qian Zhang, Dingyuan Zhang, Xiaoqing Xin, Rui Zhang, Fenguo Zhou, Dewen Dong
PMID23391000
ABSTRACT
A facile and efficient synthesis of substituted indeno[2,1-c]quinolin-6(7H)-ones from a variety of α-acyl N-arylcinnamamides mediated by polyphosphoric acid (PPA) is described, and a mechanism involving the formation of a dicationic superelectrophile and subsequent double intramolecular nucleophilic cyclization reactions is proposed.