Reduction of 4,5-Dihydro-1,2-oxazoles (Δ2-Isoxazolines); A Cycloadditive Approach to 2-Alkenyl Ketones

Article abstract of DOI:10.1055/s-1986-31595

A new cycloadditive route to 2-alkenyl ketones (β,γ-unsaturated ketones) involves: (1) nitrile oxide-allylsilane (or stannane) cycloaddition, (2) reductive cleavage of the resultant isoxazoline, and (3) Peterson elimination.In all cases, the products are not contaminated by the isomeric 1-alkenyl ketones.Although stereoselectivity in the nitrile oxide cycloaddition to 3-trimethylsilyl-1-butene is low, the resultant diastereomeric cycloadducts can be converted stereospecifically to the corresponding (E)- and (Z)-olefins.