Hicks FA,
Buchwald SL.
*
Massachusetts Institute of Technology, Cambridge, USA
Highly Enantioselective Catalytic Pauson–Khand Type Formation of Bicyclic Cyclopentenones.
J. Am. Chem. Soc. 1996;
118: 11688-11689
DOI:
10.1021/ja9630452
Key words
titanium catalysis - Pauson–Khand type reaction - asymmetric synthesis - bicyclic
cyclopentenones
Significance
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.
Comment
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.
Review
S. E. Gibson (née Thomas), A. Stevenazzi Angew. Chem. Int. Ed. 2003, 42, 1800–1810.
