title: Photochemical reactions of tetrachloro-1,4-benzoquinone (chloranil) with tricyclo[4.1.0.0(2,7)]heptane (Moore's hydrocarbon) and bicyclo[4.1.0]hept-2-ene (2-norcarene).
abstract: Solutions of chloranil (CA) in benzene were irradiated in the presence of Moore's hydrocarbon (MH) and 2-norcarene (NC). These reactions brought about four common products, namely 2,3,5,6-tetrachlorohydroquinone (TCH) and three 1 : 1 cycloadducts, whose C7H10 subunits were reorganised in comparison to the skeletons of MH and NC. As the fifth product, a norcar-3-en-2-yl ether of TCH was formed in the case of NC, whereas MH gave rise to a substance having the structure of the diastereomeric bis(endo-2-norcaryl) ethers of TCH. A control experiment demonstrated that this substance is also produced from MH and TCH without irradiation. In view of the known addition of acids onto MH to give norcaranes substituted in position 2 and the known acid-catalysed isomerisation of MH to NC, it seems obvious that TCH was the only genuine product of the photoreaction of CA with MH. Being an acid, TCH then not only took up two equivalents of MH furnishing the bisethers referred to but also catalysed the rearrangement of MH to NC, which served as a substrate for excited CA to yield the three 1 : 1 cycloadducts mentioned.
authors.affiliation: Institute of Organic Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany. christl@chemie.uni-wuerzburg.de
authors.forename: Manfred
authors.initials: M
authors.lastname: Christl
authors.forename: Max
authors.initials: M
authors.lastname: Braun
authors.forename: Oliver
authors.initials: O
authors.lastname: Deeg
mesh_terms: D001643:Bridged Bicyclo Compounds / Q000737:chemistry*; D002703:Chloranil / Q000737:chemistry*; D006873:Hydroquinones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D055668:Photochemical Processes
chemical_list: D001643:Bridged Bicyclo Compounds; D006873:Hydroquinones; D002703:Chloranil; C044578:2,3,5,6-tetrachlorohydroquinone