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Reaction of secondary phosphine oxides with acylacetylenes

“…The 1 H, 13 C, and 31 P NMR spectra were measured from solutions in CDCl 3 on a Bruker DPX-400 instrument (400.13, 101.61, and 161.98 MHz, respectively); the chemical shifts were determined relative to hexamethyldisiloxane ( 1 H, 13 C) or 85% phosphoric acid ( 31 P). Signals in the NMR spectra were assigned using two-dimensional homoand heteronuclear correlation techniques (HSQC, HMBC, NOESY).…”

“…They are widely used as ligands for metal complex catalysts [1][2][3], special solvents for stabilization of nanosystems in the synthesis of semiconductors [4], extractants for noble, rare-earth, and transuranium elements [5][6][7], fire-retardants [8], and photochromic [9] and luminescent materials [10]. Phosphine oxides are successfully used as building blocks, e.g., in the Wittig-Horner reaction [11][12][13][14], specifically, for the synthesis of substituted vitamin D 3 analogs [14]. Of particular interest are polyfunctionalized tertiary phosphine oxides; however, their synthesis involves some difficulties.…”

“…However, adducts IIIa and VIa at the carbonyl group were shown ( 1 H, 13 C, and 31 P NMR monitoring) to undergo decomposition into initial acetylacetylene IIa and the corresponding phosphine oxide I or V on heating in CDCl 3 (50-55°C, 7-33 h; Scheme 4). The conversion of phosphine oxide IIIa was ~90% in 13 h, while the conversion of VIa was only ~15% over the same period of time.…”