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Reductive Aldol Coupling of Divinyl Ketones via Rhodium-Catalyzed Hydrogenation:  syn-Diastereoselective Construction of β-Hydroxyenones

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journal contribution
posted on 23.11.2006, 00:00 by Soo Bong Han, Michael J. Krische
Catalytic hydrogenation of divinyl ketones 1a and 1e in the presence of diverse aldehydes 2ae at ambient temperature and pressure using cationic rhodium catalysts ligated by tri-2-furyl phosphine enables formation of aldol products 3ae and 5a−e, respectively, with high levels of syn diastereoselection. Through an assay of counterions (Rh(COD)2X), Rh(COD)2SbF6 is identified as the optimum precatalyst for reductive aldol couplings of this type. For para-substituted styryl vinyl ketones 1be, a progressive increase in isolated yield is observed for electron-releasing para substituents.