244033-83-8Relevant academic research and scientific papers
An intramolecular oxo Diels-Alder approach to 1-oxo-1,2,3,3a,4,7a- hexahydro-pyrano[3,4-c]pyrrole-4-carboxylic acid ethyl esters
Murray, William V.,Mishra, Pranab K.,Turchi, Ignatius J.,Sawicka, Dorota,Maden, Amy,Sun, Sengen
, p. 8955 - 8961 (2007/10/03)
The diastereoselective synthesis of a series of 1-oxo-1,2,3,3a,4,7a- hexahydro-pyrano[3,4-c]pyrrole-4-carboxylic acid ethyl esters via an oxo Diels-Alder reaction is described. Ab initio calculations predicted the products of the exo cycloaddition to be the thermodynamic products while the products resulting from the endo cycloaddition were predicted to be the kinetic products. The calculations were born out by experimental data.
Synthesis of densely functionalized pyrrolidinone templates by an intramolecular oxo-Diels-Alder reaction
Murray, William V.,Mishra, Pranab K.,Sun, Sengen,Maden, Amy
, p. 7389 - 7392 (2007/10/03)
Preparation of densely functionalized pyrrolidinone templates, is a challenge for synthetic chemists. These templates are important building blocks for novel conformationally constrained natural products or for library generation of highly functionalized
Diels-Alder Reactions of Amino Acid-Derived Trienes
Murray, William V.,Sun, Sengen,Turchi, Ignatius J.,Brown, Frank K.,Gauthier, A. Diane
, p. 5930 - 5940 (2007/10/03)
Triene precursors (1a-e, 2a-k) were constructed for substrate-controlled asymmetric Diels-Alder reactions. Boc-L-phenylalanal and Boc-L-valinal were condensed with triethyl phosphonoacetate or 2-phosphonopropionate to generate the α,β-unsaturated esters as dienophiles. Removal of the Boc group to give free amines 4a-d, which after, or without N-benzylation, were treated with 3,5-hexadienoyl chloride to give 1a-e, or with 2,4-hexadienoyl chloride to afford 2a-f. The trienes 2g-i were prepared via reductive alkylation of amines 4a-i with 2,4-hexadienal. The secondary amide triene 1a failed to yield any Diels-Alder product when heated at 170°C. The tertiary amide trienes 1b-e produced in refluxing toluene the major cycloaddition products that were cis-fused and derived from the exo transition states. Trienes 2a-k underwent surprisingly facile Diels-Alder reactions to produce the major trans-fused isomers that were derived from the endo transition states. For trienes 2b-h and 2j,k, Diels-Alder reactions proceeded at room temperature. For the primary amide 2a, the Diels-Alder reaction proceeded smoothly in refluxing toluene. The tertiary amide triene 22 was constructed to have two electron-withdrawing ester substituents at the termini of the triene. The Diels-Alder reaction of 22 took place spontaneously at room temperature upon benzoylation of the secondary amine 21 and produced a single isomer derived from the endo transition state. 1,3-Allylic strain is discussed as an important factor in control of the diastereo-selectivity.
