Hydrogen-Mediated Aldol Reductive Coupling of Vinyl Ketones Catalyzed by Rhodium: High <i>Syn</i>-Selectivity through the Effect of Tri-2-furylphosphine
作者:Cheol-Kyu Jung、Susan A. Garner、Michael J. Krische
DOI:10.1021/ol052859x
日期:2006.2.1
[GRAPHICS]Catalytic hydrogenation of methyl vinyl ketone (MVK) and ethyl vinyl ketone (EVK) in the presence of diverse aldehydes at ambient temperature and pressure using tri-2-furylphosphine-ligated rhodium catalysts enables formation of aldol products with high levels of syn-diastereoselectivity. A progressive increase in diastereoselectivity is observed upon sequential replacement of phenyl residues for 2-furyl residues (Ph3P, FurPh(2)P, Fur(2)PhP, Fur(3)P). Hydrogen-labile functional groups, including alkynes, alkenes, benzylic ethers, and nitroarenes, remain intact under the coupling conditions.
Diastereo- and Enantioselective Hydrogenative Aldol Coupling of Vinyl Ketones: Design of Effective Monodentate TADDOL-Like Phosphonite Ligands
作者:Cisco Bee、Soo Bong Han、Abbas Hassan、Hiroki Iida、Michael J. Krische
DOI:10.1021/ja710862u
日期:2008.3.1
the first enantioselective reductive aldol couplings of vinyl ketones, which were achieved through the design of a novel monodentate TADDOL-like phosphonite ligand. Specifically, hydrogenation of commercially available methyl vinyl ketone (MVK) or ethyl vinyl ketone (EVK) in the presence of aldehydes 1a-7a using cationic rhodium catalysts modified by chiral TADDOL-like phosphonite ligands AP-I and AP-IV