3-BROMO-2-PYRONE - AN EASILY PREPARED CHAMELEON DIENE AND A SYNTHETIC EQUIVALENT OF 2-PYRONE IN THERMAL DIELS-ALDER CYCLOADDITIONS

[摘要] 3-Bromo-2-pyrone, a stable solid prepared by a new route (eq. 1), has been found to undergo smooth and regiospecific 2+4-cycloadditions between 78-90-degrees-C with both electron-rich and electron-deficient dienophiles; subsequent high-yield reductive debrominations produced halogen-free cycloadducts thus showing 3-bromo-2-pyrone to be a practical and effective synthetic equivalent of 2-pyrone in thermal Diels-Alder cycloadditions.

[发布日期] 1991-09-23