A novel visible-light promoted sulfonylation/ipso-cyclization of N-arylpropiolamides with arylamines and DABCO·(SO2)2 to synthesize various sulfonated spiro[4,5]trienones is reported. This sulfonylation/ipso-cyclization reaction proceeds via a radical process and undergoes arylsulfonyl radical formation, sulfonylation, and ipso-cyclization. The experimental results indicate that H2O provides an oxygen atom for the construction of the carbonyl group.
![Graphical abstract: Visible-light promoted one-pot synthesis of sulfonated spiro[4,5]trienones from propiolamides, anilines and sulfur dioxide under transition metal-free conditions](http://hg.y866.cn/compound/lib/scimg/usr/1/C9CC05949K.jpg)
