A reaction of gamma-silyl allylic alcohol and its ether with ozone provides synthetically versatile alpha-formyl silyl peroxide in good yield without normal fission of carbon-carbon double bond. Thus, the provided silyl peroxide serves as a good precursor for the stereochemically defined triol derivative via alkylation and reduction of peroxide moiety.
Oxidative alkynylation of acrylate esters with propargylic alcohols giving conjugated enyne esters was realized by use of a diene–rhodium catalyst. Propargylic alcohols were found to be useful alkynylating reagents in the present reaction to produce alkynylrhodium species via carbon–carbon bond cleavage. An excess of the acrylate ester worked as a hydride acceptor to reproduce the active rhodium species
The reaction of alkenylsilanes with ozone provides synthetically versatile β-hydroxy or α-formyl silyl peroxides in good yield without normal fission of the C=C bond. The obtained α-formyl silyl peroxides serve as good precursors for the stereochemically defined diol or triol derivatives via nucleophilic addition to the formyl group and reduction of the peroxide moiety.
Cross-Hyperconjugation: An Unexplored Orbital Interaction between π-Conjugated and Saturated Molecular Segments
作者:Rikard Emanuelsson、Andreas Wallner、Eugene A. M. Ng、Joshua R. Smith、Djawed Nauroozi、Sascha Ott、Henrik Ottosson
DOI:10.1002/anie.201206030
日期:2013.1.14
Crossing a barrier: Molecules with saturated ER2 units (E=C or Si, R=electron‐releasing group) inserted between two π‐conjugated segments have electronic and optical properties that resemble those of cross‐conjugated molecules (see figure). This cross‐hyperconjugation provides a deeper understanding of the conjugation phenomenon, and is an alternative to cross‐conjugation in the design of molecules