Asymmetric Diels–Alder Reaction of Aminodienes with a Nonracemic Acrylate Bound to Rink Resin: A Comparison of These Reactions with Their Solution-State Analogues
derivatives and three N-Z-protected 1-aminodienes have been investigated both in solution and on a solid support. Comparable results for each reaction were observed with the formation of the corresponding constrained cyclic s-amino acids in high yield and moderate-to-good selectivity when using optimized conditions. A detailed comparison of both solution and solid-support synthesis by conventional heating
Constrained enantiopure bicyclic β-amino acids derivedfrom the asymmetric Diels–Alder reaction of the (R)-benzyl-4-(3-acryloyloxy-4,4-dimethyl-2-oxopyrrolidin-1-yl)-benzoate and the 1-(benzyloxycarbonylamino)cyclohexadiene provide original templates for the construction of new rigid enantiopure 1,3-amino alcohols.
Effect of the cross-linker on the general performance and temperature dependent behaviour of a molecularly imprinted polymer catalyst of a Diels–Alder reaction
作者:Henning Henschel、Nicole Kirsch、Jimmy Hedin-Dahlström、Michael J. Whitcombe、Susanne Wikman、Ian A. Nicholls
DOI:10.1016/j.molcatb.2011.06.006
日期:2011.11
Here we present a series of molecularly imprinted polymers capable of catalysing the Diels-Alder reaction between benzyl 1,3-butadienylcarbamate (1) and N,N-dimethyl acrylamide (2). The polymer systems studied here demonstrated an unusual cross-linker and temperature dependent behaviour, namely that polymer catalysis of the Diels-Alder reaction was lower at elevated temperature, in contrast to the solution reaction. Furthermore, not only was the catalytic activity significantly influenced by the choice of cross-linker, but in a similar fashion also the extent of the temperature effect, indicating a close relationship between catalysis and the observed inhibition. Molecular dynamics simulations of both the polymer systems studied were used to provide insight into the molecular background of transition state stabilisation, and differences in properties of the systems based on different cross-linkers. (C) 2011 Elsevier B.V. All rights reserved.