Silylated cyclohexadienes as new radical chain reducing reagents: preparative and mechanistic aspects.
Various silylated 1,4-cyclohexadienes are presented as superior tin hydride substitutes for the conduction of various radical chain reductions. Debrominations, deiodinations, and deselenations can be performed using these environmentally benign reagents. Furthermore, Barton-McCombie-type deoxygenations using silylated cyclohexadienes are described. Radical cyclizations, ring expansions, and Giese-type addition reactions with the new tin hydride substitutes are presented. The polymerization of styrene can be regulated using silylated cyclohexadienes. Rate constants for hydrogen atom abstraction from two 1-silyl-cyclohexadienes by primary C-radicals were determined. The effects of the cyclohexadiene substituents on the reaction outcomes are discussed. Finally, qualitative EPR experiments on silyl radical expulsion from silylated cyclohexadienyl radicals are presented.
Fachbereich Chemie der Universität Marburg, Hans-Meerwein-Strasse, D-35032 Marburg. studer@mailer.uni-marburg.de
Armido
A
Studer
Stephan
S
Amrein
Florian
F
Schleth
Tobias
T
Schulte
John C
JC
Walton