Na2S2O8‐Promoted Radical Cyclization for the Synthesis of Azaspiro[4.5]deca‐3,6,9‐triene‐2,8‐dione and Pyrrolo[2,1‐j]quinolone Derivatives

Abstract

An efficient radical cyclization of N‐(4‐methoxyphenyl)‐N‐methyl‐3‐phenylpropiolamides with 1‐phenylcyclopropan‐1‐ols has been developed using Na2S2O8 to produce azaspiro[4.5]deca‐3,6,9‐triene‐2,8‐diones in good yields with high selectivity. Similarly, the reaction of 1‐[6‐methoxy‐3,4‐dihydroquinolin‐1(2H)‐yl]‐3‐phenylprop‐2‐yn‐1‐ones with 1‐phenylcyclopropan‐1‐ols provides 6,7‐dihydro‐3H‐pyrrolo[2,1‐j]quinoline‐3,9(5H)‐dione derivatives. This is the first report on the use of cyclopropanols for the radical cyclization of N‐(4‐methoxyphenyl)‐N‐methyl‐3‐phenylpropiolamides and 1‐[6‐methoxy‐3,4‐dihydroquinolin‐1(2H)‐yl]‐3‐phenylprop‐2‐yn‐1‐ones.