86739-01-7Relevant academic research and scientific papers
Photochemistry of Cyclopropene Derivatives. Ring-opening Reaction of 3-Heteroaryl Substituted Cyclopropenes
Chiacchio, Ugo,Compagnini, Anna,Grimaldi, Roberto,Purrello, Giovanni,Padwa, Albert
, p. 915 - 919 (2007/10/02)
The photochemical rearrangement of several 3-heteroaryl substituted cyclopropenes has been studied.The rearrangements are derived from the ?-?* singlet state of the cyclopropene.Ring opening occurs to give a vinylcarbene intermediate which undergoes a subsequent electrocyclization.The transient intermediate so produced can undergo either a 1,3- or a 1,5-sigmatropic hydrogen shift to give the observed products.One strong piece of evidence for carbene intervention is the observation of a 1,3-butadiene derivative as one of the photoproducts obtained from the photolysis of a 3-pyrrolyl substituted cyclopropene.The 1,3-diene is thought to be derived by insertion of the vinylcarbene into the neighbouring methyl group.The regioselectivity of the rearrangement can be accounted for in terms of competitive 1,3- and 1,5-sigmatropic hydrogen migrations.
