Self‐assembled catalyst: A new kind of chiral supramolecular organocatalyst, self‐assembled from chiral amines and poly(alkene glycol)s, was developed. The resulting self‐assemblies were found to be highlyefficient in the asymmetriccatalysis of the unusual Diels–Alder reaction between cyclohexenones and nitrodienes, nitroenynes or nitroolefins, giving excellent chemo‐, regio‐ and enantioselectivities
N-Heterocyclic Carbene Catalyzed Homoenolate-Addition Reaction of Enals and Nitroalkenes: Asymmetric Synthesis of 5-Carbon-Synthon δ-Nitroesters
作者:Biswajit Maji、Li Ji、Siming Wang、Seenuvasan Vedachalam、Rakesh Ganguly、Xue-Wei Liu
DOI:10.1002/anie.201203449
日期:2012.8.13
Synthesizing synthons: The highly enantioselective title reaction is described. It employs catalytic amounts of N‐heterocyclic carbene precursors and transforms a broad range of nitroalkenes, such as nitrodienes, nitroenynes, and nitrostyrenes, through reaction with a broad range of enals, into δ‐nitroesters via homoenolate intermediates (see scheme).
Reduced graphene oxide supported piperazine in aminocatalysis
作者:Eduardo Rodrigo、Beatriz García Alcubilla、Raquel Sainz、J. L. García Fierro、Rafael Ferritto、M. Belén Cid
DOI:10.1039/c4cc02701a
日期:——
Reduced graphene oxide (rGO) has been used as a support for piperazine to provide a heterogeneous bifunctional organocatalyst (rGO-NH) that is able to efficiently promote vintage organic transformations such as Knoevenagel, Michael and aldol reactions. The obtained results suggest a significant role of the support in the course of these reactions.
A highly regio- and enantioselective organocatalyzed Michael addition of malonates to nitrodienes
作者:Raghunath Chowdhury、Ganga B. Vamisetti、Sunil K. Ghosh
DOI:10.1016/j.tetasy.2014.02.007
日期:2014.4
An organocatalyzed direct Michael addition of unsubstituted/substituted malonates, acetoacetate, or acetylacetones to conjugatednitrodienes using a cinchona alkaloid-based thiourea catalyst is disclosed. The addition products were formed in high yields and regioselectivity. The enantioselectivities of the addition products were high in most cases and could significantly be improved upon by a single