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. ... Theory predicts that electron donors have larger outward rotation preferences than acceptors in thermal ring openings of cyclobutenes. Experimental verifications are presented for several 3,3-disubstituted cyclobutenes. ... Experimental verification of torquoselectivities of 3,3- ...