Catalytic enantioselective construction of all-carbon quaternary stereocenters by an organocatalytic Diels–Alder reaction of α-substituted α,β-unsaturated aldehydes
A binaphthyl-based primary amine (R)- was designed for the Diels-Alderreaction of alpha-substituted alpha,beta-unsaturated aldehydes; in the presence of the TfOH salt of (R)-, the Diels-Alderreaction of alpha-substituted alpha,beta-unsaturated aldehydes with cyclopentadiene proceeded to afford the corresponding cycloadducts having one all-carbon quaternary stereocenter in good yield with good to
Enantioselective Diels–Alder Reaction of α-Acyloxyacroleins Catalyzed by Chiral 1,1′-Binaphthyl-2,2′-diammonium Salts
作者:Akira Sakakura、Kenji Suzuki、Kazuaki Ishihara
DOI:10.1002/adsc.200600322
日期:2006.11
activity and enantioselectivity for the Diels–Alder reaction of α-acyloxyacroleins. For example, in the presence of 5 mol % of 2a and 9.5 mol % of Tf2NH, the Diels–Alder reaction of α-(cyclohexanecarbonyloxy)acrolein with cyclopentadiene proceeded in EtCN at −75 °C to give the adducts in 88 % yield with 92 % exo and 91 % ee. The electron-donating property of the acyl group of the α-acyloxyacroleins increases
Asymmetric Morita-Baylis-Hillman Reaction of Arylaldehydes with 2-Cyclohexen-1-one Catalyzed by Chiral Bis(Thio)urea and DABCO
作者:Min Shi、Xu-Guang Liu
DOI:10.1021/ol7028806
日期:2008.3.1
Novel bis(thio)urea organocatalysts were synthesized from axially chiral (R)-(-)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl-2,2'-diamine (H-8-BINAM), and their catalytic abilities have been examined in the Morita-Baylis-Hillman reaction of 2-cyclohexen-1-one or 2-cyclopenten-1-one with a wide range of aromatic aldehydes in combination with DABCO. The best result was achieved in the reaction of 3-fluorobenzaldehyde with 2-cyclohexen-1-one to give the desired Morita-Baylis-Hillman product in 79% yield and 88% ee.
BINAM and H8-BINAM-based chiral imines and Zn(OTf)2-catalyzed enantioselective Friedel–Crafts alkylation of indoles with nitroalkenes
作者:Zhi-Liang Yuan、Zhi-Yu Lei、Min Shi
DOI:10.1016/j.tetasy.2008.04.037
日期:2008.6
Axially chiral imine ligands derived from (R)-BINAM are effective chiral ligands in the Zn(OTf)(2)-promoted enantioselective Friedel-Crafts alkylation of indoles with nitroalkenes under mild conditions to give the corresponding adducts in good yields and moderate enantioselectivities. (C) 2008 Elsevier Ltd. All rights reserved.