摘要：

Treatment of acylnitroso hetero DielsAlder cycloadducts 2 with iron(III) or copper(II) in an alcohol solvent induces ring opening to afford predominantly monocyclic anti -1,4-hydroxamic acids 3 . However, treatment of cycloadducts 2 with copper(II) in toluene reverses the stereoselectivity of the ring opening to afford syn -1,4-hydroxamic acids 4 . These regio- and stereoselective processes separately provide anti -1,4- and syn -1,4-disubstituted cyclopentenes while regenerating a hydroxamic acid moiety, thus enhancing the chemical versatility of the DielsAlder cycloadducts.

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