Catalytic Enantioselective Conjugate Addition of Carbamates
摘要:
Catalytic, asymmetric conjugate addition of carbamates to enoyl systems has been realized for the first time, providing a two-step access to virtually enantiopure N-protected beta-amino acids.
Highly Enantioselective Friedel−Crafts Alkylations of Pyrroles and Indoles with α‘-Hydroxy Enones under Cu(II)-Simple Bis(oxazoline) Catalysis
作者:Claudio Palomo、Mikel Oiarbide、Bharat G. Kardak、Jesús M. García、Anthony Linden
DOI:10.1021/ja0423217
日期:2005.3.1
Remarkably high and regular enantioselectivities are obtained in Friedel-Craftsalkylation reactions involving alpha'-hydroxy enone templates and Cu(II)-bis(oxazoline) complexes as catalysts. The simple elaboration of adducts provides a route to enantioenriched aldehydes, carboxylic acids, and ketones containing the pyrrole and indole frameworks.
A convergent regiospecific synthesis of zirconium enolates
作者:Aleksandra Kasatkin、Richard J. Whitby
DOI:10.1016/j.tet.2003.09.022
日期:2003.12
α-Lithiated phenylsulphonyloxiranes insert into alkenylzirconocene chlorides with loss of phenylsulphinate to give zirconyloxiranes which smoothly rearrange by either α- or β- C–O cleavage to afford regiodefined zirconium enolates which may be further elaborated.
Catalytic Enantioselective Conjugate Addition of Carbamates
作者:Claudio Palomo、Mikel Oiarbide、Rajkumar Halder、Michael Kelso、Enrique Gómez-Bengoa、Jesús M. García
DOI:10.1021/ja047004e
日期:2004.8.1
Catalytic, asymmetric conjugate addition of carbamates to enoyl systems has been realized for the first time, providing a two-step access to virtually enantiopure N-protected beta-amino acids.
Catalytic Enantioselective Conjugate Addition of Nitromethane to α′-Hydroxy Enones as Surrogates of α,β-Unsaturated Carboxylic Acids and Aldehydes
作者:Claudio Palomo、Raquel Pazos、Mikel Oiarbide、Jesús M. García
DOI:10.1002/adsc.200606076
日期:2006.7
No base is required for the Mg(II)-catalyzed conjugate addition of nitromethane to α′-hydroxy enones in the presence of molecular sieves. Good enantioselectivities are attained using 3 or 4 Å MS and about 10 mol % of Mg(OTf)2-chiral bisoxazoline complexes. Elaboration of the adducts through oxidative cleavage of the ketol moiety provides an entry to enantioenriched γ-nitro carboxylic acids, while a