Phosphinate, phenyl-, ethyl ester

P02CgH], Phosphinic acid, phenyl-, ethyl ester, ( )-, [111611-87-1], 31 144... 

Trimethylbenzoylphenyl phosphinic acid ethyl ester. See Ethyl (2,4,6-trimethylbenzoyl), phenyl phosphinate... 

Photolytic decomposition of peroxides is not v y efBcient in crosslinking. An enhancement effect on the extent of photocrosslinking of polyolefins in the presence of peroxides is displayed by aromatic hydrocarbons such as naphthalene. These transfer the exdtation energy absorbed to a peroxide. This procedure, however, does not represent an important improvement when compared with that refored to earlier, namely the photoreduction of pdyethylene with aromatic ketones and quinones [84. From aromatic ketones and quinones, particulariy bena>phenone [32], chlorinated benzophenones, benzoyl-l-( dohexanol [82], a, -dimethot - hen acdr henone, 2,4,6-trimethyl benzoyl phenyl phosphinic ethyl ester [85], anthrone [86], anthraqui-none [87], naphthoquinone, benzoquinone, and their d vatives have all been examined. 

To assess the stereospecificity of the Grignard and organolithium reactions with menthyl phosphinates, the diastereomeric purity of starting menthyl esters was estimated by pmr spectroscopy (see Sect. 2.2) and, in most cases, highest reported rotations were used to estimate the. enantiomeric purity of the derived optically active phosphine oxides The method of preference for determining the enantiomeric purity of a phosphine oxide, even in those cases in which a value for the rotation of optically pure material is reported, involves stereospecific reduction of the phosphine oxide with hexa-chlorodisilane (see Sect. 2.4) to the corresponding phosphine, followed by quatemization with 2-phenyl-2-methoxy-ethyl bromide and pmr analysis of the diastereomeric phosphonium bromides (Eq. (1)) > This method for determining optical purity, shown ) to be applicable... 

Triethyl phosphite added dropwise during 2 hrs. at 160° to a suspension of NiClg in bromobenzene with distillation of the resulting ethyl bromide, and heating continued ca. 0.5 hr. -> diethyl benzenephosphonate. Y 91%. - Similarly with diethyl benzenephosphonite and 2-bromothiophene, after subsequent 3 hrs. reflux with NaOH in methanol -> phenyl-2-thienylphosphonic acid. Y 82%. F. e., also phosphinic acid esters, and with NiBrg, limitations, s. P. Tavs, B. 103, 2428 (1970) Tetrahedron 26, 5529 (1970). 

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