摘要：

The reaction of conjugated ene-yne-ketones 3 with a variety of alkenes in the presence of a catalytic amount of Cr(CO)5(THF) at room temperature gives (2-furyl)cyclopropanes in good yields. These cyclopropanation reactions proceed via (2-furyl)carbene-chromium intermediates 4 formed in situ from ene-yne-ketones 3. Late transition metals, such as [RuCl2(CO)3]2, [RhCl(cod)]2, PdCl2, and PtCl2, also catalyze effectively the cyclopropanation of styrene with 3.

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