Diazepane Carboxylates as Organocatalysts in the Diels-Alder Reaction of α-Substituted Enals
作者:Nicklas O. Häggman、Benjamin Zank、HyunJune Jun、Dainis Kaldre、James L. Gleason
DOI:10.1002/ejoc.201801009
日期:2018.10.24
Diazepane carboxylates efficiently catalyze the Diels–Alder cycloaddition of α‐substituted enals with a range of dienes. With chiral diazepane backbones, weak electrostatic interactions favour diene approach from the more hindered face, leading to enantioselectivities of 70–95 % with a range of dienophiles.
Asymmetric Diels-Alder Reaction of α-Substituted and β,β-Disubstituted α,β-Enals via Diarylprolinol Silyl Ether for the Construction of All-Carbon Quaternary Stereocenters
作者:Yujiro Hayashi、Bojan P. Bondzic、Tatsuya Yamazaki、Yogesh Gupta、Shin Ogasawara、Tohru Taniguchi、Kenji Monde
DOI:10.1002/chem.201602345
日期:2016.10.24
Diels–Alder reaction of α‐substituted acrolein proceeds in the presence of the trifluoroacetic acid salt of trifluoromethyl‐substituted diarylprolinol silylether to afford the exo‐isomer with both excellent diastereoselectivity and high enantioselectivity. In the Diels–Alder reaction of a β,β‐disubstituted α,β‐unsaturated aldehyde, good exo‐selectivity and excellent enantioselectivity was obtained when the
Homogeneous catalysis: use of chiral titanocene complexes for asymmetric catalytic Diels–Alder reactions
作者:William Odenkirk、B. Bosnich
DOI:10.1039/c39950001181
日期:——
A stable, chiral diaquo titanocene complex is an excellent catalyst for certain DielsâAlder reactions giving good enantioselectivity which indicates that catalysis occurs by metal rather than by proton activation of the dienophile.
A New Cationic, Chiral Catalyst for Highly Enantioselective Diels−Alder Reactions
作者:Kevin T. Sprott、E. J. Corey
DOI:10.1021/ol034706k
日期:2003.7.1
[reaction: see text] The Diels-Alder reaction of cyclopentadiene and 2-methacrolein is catalyzed by a chiral Lewis acid to form the exo adduct in 96% yield and 96% ee.
supramolecular boron Lewisacidcatalysts were prepared from chiral 3-phosphoryl-1,1′-bi-2-naphthols, (2-cyanophenyl)boronic acids, and tris(pentafluorophenyl)borane, bound through CN···B and PO···B coordination bonds. In particular, the coordinated tris(pentafluorophenyl)boranes increase the Lewis acidity of the active center in the manner of a LewisacidassistedLewisacidcatalyst system. A possible