133145-64-9Relevant academic research and scientific papers
HIGH DIASTEREOSELECTIVITY IN THE CYCLIZATION OF 1,5-BIRADICALS: WHAT CAUSES SUCH SIZEABLE STERIC BARRIERS TO BIRADICAL COUPLING?
Wagner, Peter J.,Park, Bong Ser
, p. 165 - 168 (1991)
The high diastereoselectivities observed in the photocyclization of α-(o-ethylphenyl)acetophenones appear to reflect conformational equilibria in the triplet 1,5-biradical intermediates rather than steric barriers created during cyclization.The necessary biradical triplet -> singlet intersystem crossing is proposed to occur along the cyclization reaction coordinate since the orthogonality of the two singly-occupied p orbitals does not depress biradical lifetimes.
