Efficient Synthesis of Highly Enantioenriched Δ1-Pyrrolines
摘要:
A general and efficient asymmetric synthesis of (1)-pyrrolines by a one-pot nitro-reduction, cyclization, and dehydration of (R,E)-1,5-diphenyl-3-(nitromethyl)-5-pent-4-en-1-ones with iron and aqueous hydrochloric acid has been developed. The (1)-pyrrolines were obtained with excellent enantioselectivities (up to 99%) and high yields (up to 83%).
Highly Enantioselective 1,4-Michael Additions of Nucleophiles to Unsaturated Aryl Ketones with Organocatalysis by Bifunctional Cinchona Alkaloids
作者:Cristina G. Oliva、Artur M. S. Silva、Diana I. S. P. Resende、Filipe A. A. Paz、José A. S. Cavaleiro
DOI:10.1002/ejoc.201000273
日期:——
The development of general and efficient asymmetric organocatalytic additions of malononitrile and nitromethane to 1,5-diarylpenta-2,4-dien-1-ones (cinnamylideneacetophenones) catalyzed by cinchona organocatalysts is reported. The reactions afforded excellent enantioselectivities (up to 99 %), high yields (up to 97 %), and exclusive 1,4-addition regioselectivities. The potential of these new enantioselective
Highly Enantioselective Michael Addition of Aromatic Ketones to Nitrodienes and the Application to the Synthesis of Chiral γ-Aminobutyric Acid
作者:Xin-Yan Wu、Xing-Tao Guo、Feng Sha
DOI:10.1055/s-0036-1588604
日期:——
oic acid. A highly enantioselective Michaeladdition of aromatic ketones to α,β,γ,δ-unsaturated nitro compounds is described. In the presence of a chiral primary amine-thiourea based on dehydroabietic amine, γ-nitro ketones were obtained in excellent enantioselectivities (up to 95% ee) with up to 95% yield. In addition, this methodology has been successfully applied in the asymmetric synthesis of chiral