Irradiation of methyl diazomalonate in solution. Reactions of singlet and triplet carbenes with carbon-carbon double bonds
作者:Maitland Jones、Wataru Ando、Michael E. Hendrick、Anthony Kulczycki、Peter M. Howley、Karl F. Hummel、Donald S. Malament
DOI:10.1021/ja00776a032
日期:1972.10
Dicarbomethoxycarbene. A Laser Flash Photolysis Study
作者:Jen-Lung Wang、John P. Toscano、Matthew S. Platz、Valerij Nikolaev、Vladimir Popik
DOI:10.1021/ja00125a007
日期:1995.5
Dimethyl diazomalonate (1) was studied by laser flash photolysis (LFP) techniques. LFP of 1 generates dicarbomethoxycarbene (2), which can be intercepted with pyridine to give a UV-vis active ylide. Analysis of the yield of ylide as a function of pyridine concentration provides estimates of the carbene lifetime in various solvents, of its rate constant for Wolff rearrangement, of its reaction with various quenchers, and of intersystem crossing.
Cyclopropane−Aldehyde Annulations at Quaternary Donor Sites: Stereoselective Access to Highly Substituted Tetrahydrofurans
作者:Austin G. Smith、Michael C. Slade、Jeffrey S. Johnson
DOI:10.1021/ol200395e
日期:2011.4.15
A diastereoselective synthesis of pentasubstituted tetrahydrofurans via a Lewis acid catalyzed (3 + 2)-annulation of quatemary donor site cyclopropanes and aldehydes is described. The reaction is catalyzed by Sn(OTf)(2), SnCl4, or Hf(OTf)(4) in yields up to 95% and diastereomeric ratios as high as 99:1.