Percarboxylic Acid Oxidation of α-Hydroxy-Substituted Alkoxy­allenes: The Unexpected Formation of Acyloxy-Substituted 1,2-Diketones and the Synthesis of Functionalized Quinoxalines

Abstract

Synthesis and NMR spectroscopic data of starting materials page 2-5 References page 5 Copies of spectra page 6-20 General Information: Reactions were generally performed under argon in flame-dried flasks. Solvents and reagents were added by syringes. Solvents were dried using standard procedures. Reagents were purchased and were used as received without further purification unless stated. Reactions were monitored by thin-layer chromatography (TLC). Products were purified by column chromatography on silica gel (32-63 μm). Unless otherwise stated, yields refer to chromatographically homogeneous and spectroscopically pure materials (1 H-NMR spectroscopy). NMR spectra were recorded with JEOL (ECX 400, Eclipse 500) instruments. Chemical shifts are reported relative to TMS (1 H: δ = 0.00 ppm) and CDCl3 (13 C: δ = 77.0 ppm). Integrals are in accordance with assignments; coupling constants are given in Hz. 13 C-NMR spectra are 1 H-decoupled. Multiplicity is indicated as follows: s (singlet), d (doublet), t (triplet),