Abstract Acetonyl radicals created by action of di-t-butylperoxide on acetone (molar ratios acetone/acetylenic compound/DTBP= 20/1/0.2; 150 C; 3h) add to acetylenic compounds and lead to the formation of 1/1 adducts in low to moderate yields. 2/1 adducts are not observed in these experimental conditions.