485385-81-7Relevant articles and documents
Cycloisomerization – a straightforward way to benzo[h]quinolines and benzo[c]acridines
Shestakov, Aleksandr N.,Pankova, Alena S.,Kuznetsov, Mikhail A.
, p. 1103 - 1113 (2017/12/08)
[Figure not available: see fulltext.] Cycloisomerization of 3-alkynyl-2-arylpyridines and quinolines offers a straightforward approach to benzo[h]quinolines and benzo[c]-acridines. Substituent at the triple bond governs a choice between transition metal or Br?nsted acid catalysis. A direct electrophilic activation by trifluoromethanesulfonic acid induces an almost quantitative cyclization of the o-aryl(phenylethynyl) fragment. PtCl2 efficiently catalyzes cyclization of 2-aryl-3-ethynylhetarenes.