不饱和羧酸酯的分子内Diels-Alder反应的研究

STUDY ON THE INTRAMOLECULAR DIELS-ALDER REACTION OF UNSATURATED ESTERS

本文合成(2E,4Z)-4,5-二苯基-2,4-戊二烯醇,并分别与丙烯酰氯及顺丁烯二酸酐反应生成对应的酯。研究了丙烯酸-(2E,4Z)-4,5-二苯基-2,4-戊二烯酯和顺丁烯二酸-(2E,4Z)-4,5-苯基-2,4-戊二烯单酯的分子内Diels-Alder反应,并证实这两种酯分子内环加成反应的活性有很大差异。通过NMR,IR,MS,UV等图谱分析,并运用分子轨道理论,探讨了该环加成反应的过程及其区域专一性和立体选择性。

Substrates were derived from(2E,4Z)-4,5-diphenyl-2,4-pentadienol forstudy on the intramolecular Diels-Alder reaction.It was found that the(2E,4Z)-4,5-di-phenyl-2,4-pentadienyl acrylate failed to undergo intramolecular cycloaddition at 110℃,but the highly reactive maleate half ester could produce the cis-fused cycloadduct directlyat 20℃.The products were identified by MS,IR,UV and NMR.The cycloaddition reac-tion was found to have a high stereoselectivity,and the transition state of cycloadditionwas discussed in this paper in terms of the frontier molecular orbital theory.