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 intramolecularDiels–Alderaddition, 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.