New facets in the photochemistry and thermal reaction of 2,2-diphenylmethylenecyclopropane

DOI Web Site Web Site 被引用文献1件

書誌事項

公開日
2007-01
権利情報
  • https://www.elsevier.com/tdm/userlicense/1.0/
  • https://www.elsevier.com/legal/tdmrep-license
DOI
  • 10.1016/j.jphotochem.2006.06.017
公開者
Elsevier BV

この論文をさがす

説明

Abstract Photochemistry and thermal reaction of 2,2-diphenylmethylenecyclopropane 1a have been reinvestigated to make their mechanistic refinement. A new finding in the photochemistry of 1a is the detection and isolation of cyclobutene 7 . While fragmentation and 1,3-carbon (C) shift is responsible for previously reported photoproducts, 1,1-diphenylethylene 3 and diphenylmethylenecyclopropane 2a , respectively, a new pathway is required to explain the formation of cyclobutene 7 . A mechanism involving the 1,2-C shift (Scheme 3, arrow b) followed by 1,2-hydrogen (H) shift is proposed. In the thermal reaction of 1a, on the other hand, a trimethylenemethane type of species is shown to be a common intermediate for degeneracy, rearrangement from 1a to 2a , and formation of indene 5 . In the photochemistry of 1a , intervention of cyclobutylidene 8 is strongly supported by circumstantial evidences provided by steady-state and laser flash photolytic investigations. Further experiments designed to independently generate cyclobutylidene 8 showed the methylenecyclopropane/cyclobutene branching ratio (1a / 7 ) to be in the range between 0 and 1.7, which is much lower than the value of 4.0 for parent cyclobutylidene. Nevertheless, the relative efficiency of 1,2-shift pathway to generate 8 is shown to be as high as 17–47% compared to 1,3-C shift to give 2a at the early photochemical stage of 1a .

収録刊行物

被引用文献 (1)*注記

もっと見る

問題の指摘

ページトップへ