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Titanium-Catalyzed Asymmetric Pauson–Khand Type Reaction
Highly Enantioselective Catalytic Pauson–Khand Type Formation of Bicyclic Cyclopentenones.
J. Am. Chem. Soc. 1996;
Key wordstitanium catalysis - Pauson–Khand type reaction - asymmetric synthesis - bicyclic cyclopentenones
Hicks and Buchwald reported an asymmetric titanium-catalyzed Pauson–Khand type reaction to access bicyclic cyclopentenones in excellent yields and enantioselectivity. In addition to good to excellent ee values, the reaction also tolerates 1,1-disubstituted olefins amongst its wide substrate scope; a weakness in earlier Pauson–Khand systems.
The active catalyst is generated in situ, from (S,S)-(EBTHI)TiMe2. Both temperature of the reaction and the pressure of CO impacted the yield; temperatures lower than 90 °C or pressures above and below 14 psig were observed to result in diminished conversions.
S. E. Gibson (née Thomas), A. Stevenazzi Angew. Chem. Int. Ed. 2003, 42, 1800–1810.
20 October 2020 (online)
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