Diels−Alder Reactions of Amino Acid-Derived Trienes
摘要:
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 alpha,beta-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 la failed to yield any Diels-Alder product when heated at 170 degrees C. The tertiary amide trienes 1b-e produced in refluxing toluene the major cycloaddition products that were cia-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 diastereoselectivity.
Methods for the synthesis of complex reduced isoindole, isooxyindole and isooxyquinoline libraries
申请人:Ortho-McNeil Pharmaceutical, Inc.
公开号:US06667406B1
公开(公告)日:2003-12-23
Disclosed are methods of synthesizing libraries of diverse complex hexahydroisoindole, hexahydroisooxyindole and octahydroisooxyquinoline compounds through the use of a facile intramolecular Diels Alder reaction. The invention is further directed to methods for synthesizing the libraries on solid supports. The invention is further directed to methods for identifying and isolating such hexahydroisoindole, hexahydroisooxyindole and octahydroisooxyquinoline compounds with useful and diverse activities from such libraries.
Diels−Alder Reactions of Amino Acid-Derived Trienes
作者:William V. Murray、Sengen Sun、Ignatius J. Turchi、Frank K. Brown、A. Diane Gauthier
DOI:10.1021/jo990459f
日期:1999.8.1
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 alpha,beta-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 la failed to yield any Diels-Alder product when heated at 170 degrees C. The tertiary amide trienes 1b-e produced in refluxing toluene the major cycloaddition products that were cia-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 diastereoselectivity.