Carbocations as Lewis Acid Catalysts in Diels-Alder and Michael Addition Reactions
作者:Juho Bah、Johan Franzén
DOI:10.1002/chem.201304160
日期:2014.1.20
the carbocation as a highly powerful Lewis acid catalyst for organic reactions. The stable and easily available triphenylmethyl (trityl) cation was found to be a highly efficient catalyst for the Diels–Alder reaction for a range of substrates. Catalyst loadings as low as 500 ppm, excellent yields, and good endo/exo selectivities were achieved. Furthermore, by changing the electronic properties of the
New Lewis acid catalysts for the Diels-Alder reaction
作者:T. Ross Kelly、Sanat K. Maity、Premji Meghani、Nizal S. Chandrakumar
DOI:10.1016/s0040-4039(00)99464-4
日期:1989.1
Catechol boron bromide (1) and ferrocenium hexafluorophosphate (2) function as Lewisacidcatalysts for the Diels-Alderreaction.
儿茶酚溴化硼(1)和六氟磷酸铯(2)充当Diels-Alder反应的路易斯酸催化剂。
Iodine‐Catalyzed Diels‐Alder Reactions
作者:Thiemo Arndt、Philip K. Wagner、Jonas J. Koenig、Martin Breugst
DOI:10.1002/cctc.202100342
日期:2021.6.18
The Diels-Alder cycloaddition is the most popular pericyclic reaction with numerous applications in synthesis and catalysis. We now demonstrate that we can perform this reaction under mild and metal-free conditions relying on molecular iodine as the catalyst. Cycloadditions with cyclohexadiene, cyclopentadiene, or isoprene with various dienophiles can be performed typically within minutes in moderate
BBr3-chiral phosphoric acid complexes are highly effective and practical Lewis acid-assisted Brønsted acid (LBA) catalysts for promoting the enantioselective Diels-Alder (DA) reaction of α-substituted acroleins and α-CF3 acrylate. In particular, the DA reaction of α-substituted acroleins with 1,2-dihydropyridines gave the corresponding optically active isoquinuclidines with high enantioselectivities
Taming the Silylium Ion for Low-Temperature Diels-Alder Reactions
作者:Hendrik F. T. Klare、Klaus Bergander、Martin Oestreich
DOI:10.1002/anie.200904520
日期:2009.11.16
trivalent silicon cation stabilized by an electron‐rich transition metal as the “hot” Lewis acidic site catalyzes challenging Diels–Alderreactions at low temperatures with excellent reaction rates and selectivities (see scheme). In addition to the chemical stability of the silyliumion catalyst (in CH2Cl2), the potential of these reactive compounds is also discussed.