Stereochemical Memory in the Temperature-Dependent Photodenitrogenation of Bridgehead-Substituted DBH-Type Azoalkanes: Inhibition of Inverted-Housane Formation in the Diazenyl Diradical through the Mass Effect (Inertia) and Steric Hindrance
syn/anti ratio of the housanes 2 depends on the extent and type of bridgehead substitution; the amount of the anti diastereomer (retention) follows the order Ph > Me > H, and double substitution is more effective than single. This stereochemical memory is interpreted in terms of the mass effect (inertia) of the substituents and steric interaction (size) between the substituents at the bridgehead and the methylene
作者:Beck, Karin、Hoehn, Arthur、Huenig, Siegfried、Prokschy, Frank
DOI:——
日期:——
Diastereo- and Regioselective Synthesis of Diquinanes and Related Systems from Tricyclo[3.3.0.02,4]octanes by Chemical Electron Transfer (CET)
作者:Waldemar Adam、Thomas Heidenfelder、Coskun Sahin
DOI:10.1055/s-1995-4072
日期:1995.9
A new synthetic methodology for diquinanes by one-electron oxidation of tricyclo[3.3.0.02,4]octanes and subsequent stereocontrolled rearrangement is provided. The latter compounds are conveniently accessible through acid-catalyzed isopyrazole cycloaddition, followed by hydrogenation and photoextrusion of molecular nitrogen. The oxidative rearrangement of the tricyclooctanes proceeds catalytically and cleanly to afford regio- and diastereoselectively the corresponding diquinanes.