Synthesis of highly substituted allenylsilanes by alkylidenation of silylketenes.
作者信息
Marsden Stephen P, Ducept Pascal C
机构信息
School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
出版信息
Beilstein J Org Chem. 2005 Aug 26;1(1):5. doi: 10.1186/1860-5397-1-5.
BACKGROUND
Allenylsilanes are useful intermediates in organic synthesis. An attractive, convergent but little used approach for their synthesis is the alkylidenation of stable silylketenes. Reactions thus far have been limited to the use of unsubstituted silylketenes (or equivalents) with stabilised or semi-stabilised ylides only. The current study explores the reactions of substituted ketenes prepared through rhodium(II)-mediated rearrangement of silylated diazoketones.
RESULTS
A range of novel 1,3-disubstituted and 1,3,3-trisubstituted allenylsilanes were prepared using stabilised and semi-stabilised ylides. Alkylidenation with non-stabilised phosphorus ylides was not viable, but the use of titanium-based methylenating reagents was successful, allowing access to 1-substituted allenylsilanes.
CONCLUSION
Many novel allenylsilanes may be accessed by alkylidenation of substituted silylketenes. Importantly, for the first time, simple methylenation of silylketenes has been achieved using titanium carbenoid-based reagents.
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