Synthesis of 4-[(E)-1-Alkenyl]-2-hydroxybutanolides and (Z)-4-Alkylidene-2-butenolides through Cycloadditions Using a Phosphorus-Functionalized Nitrile Oxide

Abstract
A sequence of cycloadditions of (diethoxyphosphinyl)acetonitrile oxide with α,β-unsaturated esters, the Raney Ni reduction of the resulting cycloadducts, the Horner–Emmons olefination, and the carbonyl reduction with sodium borohydride leads to 5-[(E)-1-alkenyl]-3-hydroxy-4,5-dihydro-2(3H)-furanones which can be converted into (Z)-5-alkylidene-2(5H)-furanones in two steps.
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