174850-48-7Relevant academic research and scientific papers
Epimerization of cyclic vinylphosphirane complexes: The intermediacy of biradicals
Wang, Bing,Lake, Charles H.,Lammertsma, Koop
, p. 1690 - 1695 (2007/10/03)
The phosphinidene complex Ph-P-W(CO)5 reacts with cyclopentadiene, 1,3-cyclohexadiene, 1,3-cycloheptadiene, and 1,3-cyclooctadiene to give in each case isomeric mixtures of syn- and anti-vinylphosphiranes. With longer reaction times and/or higher reaction temperatures, the anti adducts isomerize to the syn adducts. These epimerizations are likely to proceed via biradical intermediates. Only the syn-vinylphosphirane of 1,3-cyclohexadiene undergoes a [1,3]-sigmatropic shift to yield a syn-phopholene. The dichotomy of biradical and concerted mechanisms is discussed in relationship with the analogous mechanism for the vinylcyclopropane → cyclopentene rearrangement.
