Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... The diphenylpropargyl cation has been shown to be a powerful Diels-Alder dienophile which adds to dienes in high yield at ambient temperatures. ... The 1,1-diphenylpropargyl cation has been generated at 25 °C and added to 1,3-dienes in a Diels-Alder reaction. Following the ...