Asymmetric Morita−Baylis−Hillman Reactions Catalyzed by Chiral Brønsted Acids
作者:Nolan T. McDougal、Scott E. Schaus
DOI:10.1021/ja037705w
日期:2003.10.1
Chiral BINOL-derived Brønstedacidscatalyze the enantioselective asymmetric Morita-Baylis-Hillman (MBH) reaction of cyclohexenone with aldehydes. The asymmetric MBH reaction requires 2-20 mol % of the chiral Brønstedacid 2e or 2f and triethylphosphine as the nucleophilic promoter. The reaction products are obtained in good yields (39-88%) and high enantioselectivities (67-96% ee). The Brønsted-acid-catalyzed
A new chiral bis-thiourea-type organocatalyst 2 developed for the Baylis–Hillmanreaction provided a drastic rate enhancement. Allylic alcohols were obtained with up to 90% ee in the case of cyclohexanecarboxaldehyde (4i).
Asymmetric Morita-Baylis-Hillman Reaction Catalyzed by Simple Amino Alcohol Derived Thioureas
作者:Alessandra Lattanzi
DOI:10.1055/s-2007-984882
日期:——
Thioureas straightforwardly derived from commercially available enantiopure amino alcohols have been found to promote the asymmetric Morita-Baylis-Hillman reaction of 2-cyclohexen-1-one and different aldehydes in the presence of triethylamine under solvent-free conditions. The corresponding allylic alcohols were obtained in good to high yields and up to 88% ee.
作者:Jian Wang、Hao Li、Xinhong Yu、Liansuo Zu、Wei Wang
DOI:10.1021/ol051822+
日期:2005.9.1
[reaction: see text] A new bifunctional binaphthyl-derived amine thiourea organocatalyst has been developed to promote enantioselective Morita-Baylis-Hillman reaction of cyclohexenone with a wide range of aldehydes. The process, catalyzed by the amine thiourea, affords synthetically valuable chiralallylic alcohol building blocks in high yields and high enantioselectivities.
High yields and enantioselectivities up to 88% were achieved in asymmetricMorita-Baylis-Hillmanreactions using a combination of chiral amino acid derived guanidines and triphenylphosphane as a novel dual catalytic system.