作者:David J. Witter、John C. Vederas
DOI:10.1021/jo952117p
日期:1996.1.1
polyketide synthase assembly of the bicyclic core of lovastatin (1) (mevinolin) by Aspergillus terreus MF 4845 was examined via the synthesis of the N-acetylcysteamine (NAC) thioester of [2,11-(13)C(2)]-(E,E,E)-(R)-6-methyldodecatri-2,8,10-enoate (5a). In vitro Diels-Alder cyclization of the corresponding unlabeled NAC ester 5b, ethyl ester 18b, and acid 20b yielded two analogous diastereomers in each
通过合成[2,11-(-)的N-乙酰半胱胺(NAC)硫辛酸酯,研究了拟由地曲霉MF 4845合成的洛伐他汀(1)(mevinolin)双环核的聚酮化合物合酶组装过程中发生的Diels-Alder环化反应。 13)C(2)]-(E,E,E)-(R)-6-甲基十二碳三烯基2,8,10-烯酸酯(5a)。在热或路易斯酸催化条件下,相应的未标记NAC酯5b,乙酯18b和酸20b的体外Diels-Alder环化在每种情况下均产生两个类似的非对映异构体。硫酯5的反应在22℃下在水性介质中容易进行。对于18b,一种产品是(1R,2R,4aS,6R,8aR)-1,2,4a,5,6,7,8,8a-八氢-2,6-二甲基萘-1-羧酸乙酯( 30)(内基产物),另一个是顺式稠合乙基(1R,2S,4aR,6R,8aR)-1,2,4a,5,6,7,8,8a-八氢-2,6-二甲基萘-1-甲酸(31)(exo产物)。通过转