Intramolecular Diels–Alder additions to 2-benzopyran-3-ones; anti-selectivity induced by the phenylsulfonyl group
作者:Edward J. Bush、David W. Jones、Firstborn Matthew Nongrum
DOI:10.1039/c39940002145
日期:——
The 2-benzopyran-3-ones 7a and 7c undergo intramolecular Diels–Alder addition, via preferred endo-addition of the connecting chain, whereas for 7d and 7e(X = SO2Ph), exo-addition of the chain is preferred; the main adducts from the latter additions (9d and 9e), give the diterpene-related products 12(R = H, Y = OMe) and 12(R = Me, Y = OMe) upon treatment with sodium amalgam.
的2-苯并吡喃-3-酮7A和7C经历分子内的Diels-Alder加成,通过优选的内切连接链的-addition,对于而图7d和图7e(X = SO 2 PH),外切链是优选的-addition; 从后者添加物中的主要加合物(9d和9e),经钠汞齐处理后,得到与二萜有关的产物12(R = H,Y = OMe)和12(R = Me,Y = OMe)。