Stereo-controlled cleavage of cyclobutanols through Ir-catalyzed C-C bond activation: Mechanistic studies and application in the Total Synthesis of (R,R,R)-alpha-tocopherol
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Beschreibung
The aim of this work was the development of new transition metal-catalyzed stereo-controlled C-C bond transformations which are at the same time atom-economic. The main focus lied on the enantioselective cleavage of cyclobutanols through iridium-catalyzed C-C bond activation. The mechanism was elucidated by means of deuteration experiments and kinetic isotope effect measurements and supported by DFT calculations. A substrate screening revealed a rather broad scope of the reaction with some limitations for certain functional groups. The new methodology was applied in the total synthesis of (R,R,R)-alpha-tocopherol to generate the quaternary center from a prochiral spiro[chromane-2,3'-cyclobutanol] unit. To introduce the aliphatic side chain of alpha-tocopherol, an unprecedented combination of enyne metathesis followed by 1,4-hydrogenation for the stereospecific synthesis of trisubstituted olefins was used.
Autor*in
Friederike Ratsch
Themen in »Stereo-controlled cleavage of cyclobutanols through Ir-catalyzed C-C bond activation: Mechanistic studies and application in the Total Synthesis of (R,R,R)-alpha-tocopherol«
Stereoselective catalysis (R,R,R)-α-tocopherol C-C bond activation