24665-54-1Relevant academic research and scientific papers
Phosphorus Compounds with Unusual Coordination, 3. Comparison of the Cycloaddition Behaviour of Diphenylketene and Triphenylphosphene
Regitz, Manfred,Urgast, Klaus,Maas, Gerhard
, p. 67 - 76 (2007/10/02)
Triphenylphosphene (3b), generated thermally or photochemically from 1b, undergoes olefination reaction with 4,5-benzotropone (6) to yield 1-(diphenylmethylen)-4,5-benzocycloheptatriene (9); the oxaphosphetane 7b is assumed to be the intermediate of this reaction.In an analogous way, 4-pyrone (15) is transformed into 4-(diphenylmethylen)pyrane (16).Corresponding olefination behaviour is observed in the reactions of 6 and 15 with diphenylketene.In the reaction of tetracyclone (20) with diphenylketene (3a), the olefination sequence leads to the formation of (diphenylmethylen) tetraphenylcyclopentadiene (21) via betain 22a and the cycloadduct 23a.The spirocyclic reaction product 26a probably arises from the same betain - like intermediate (22a *** 25a *** 26a).The analogy in triphenylphosphene reactivity towards 20 is restricted to the -cycloaddition step (formation of 26b). - Keywords: Diphenylketene, Triphenylphosphene, Cycloaddition with CO-Compounds, Crystal Structure
