Butanedione 1-phenyl

Phenyl-1,3-butadiene /t/-Phenylbutanamide Phenylbutanedioicadd, ( ) l-Phenyl-1.3-butanedione Phenyl butanoate l-PbenyM-bulaftcme... 

Phenyl-l,3-butanedione, b63 4-Phenyl-2-butanone, b77a Phenyl cellosolve, p72 Phenyl chloride, c47 Phenylcyclohexane, c376... 

This regioselectivity is practically not influenced by the nature of subsituent R. 3,5-Disubstituted isoxazolines are the sole or main products in [3 + 2] cycloaddition reactions of nitrile oxides with various monosubstituted ethylenes such as allylbenzene (99), methyl acrylate (105), acrylonitrile (105, 168), vinyl acetate (168) and diethyl vinylphosphonate (169). This is also the case for phenyl vinyl selenide (170), though subsequent oxidation—elimination leads to 3-substituted isoxazoles in a one-pot, two-step transformation. 1,1-Disubstituted ethylenes such as 2-methylene-1 -phenyl-1,3-butanedione, 2-methylene-1,3-diphenyl- 1,3-propa-nedione, 2-methylene-3-oxo-3-phenylpropanoates (171), 2-methylene-1,3-dichlo-ropropane, 2-methylenepropane-l,3-diol (172) and l,l-bis(diethoxyphosphoryl) ethylene (173) give the corresponding 3-R-5,5-disubstituted 4,5-dihydrooxazoles. 

Fig. 32.17 Mono-hydrogenation of 1 -phenyl-1,3-butanedione catalyzed by a BINAP-Ru complex.

Stereoselective hydrogenation ofl -diketones. Hydrogenation of 1,3-alkane-diones catalyzed by Ru2Cl4[(R)-l][N(C2H5)3] results in anf/-l,3-diols with high dias-tereoisomeric and enantiomeric excesses (equation I). Under the same conditions l-phenyl-l,3-butanedione (2) is reduced mainly to the (3-hydroxy ketone 3 in 98%... 

Tamariz et al. reported the synthesis of mukonine (11) based on a regioselective Diels-Alder reaction of N-phenyl-4,5-dimethylidene-2-oxazolidinone (634) with methyl propiolate (635). The diene 634 was prepared in moderate yield from the condensation reaction of 2,3-butanedione (632) with phenyl isocyanate (633). In an optimized reaction procedure using drastic basic hydrolytic conditions (KOH/ MeOH), followed by methylation with dimethyl sulfate, the adduct 636, was... 

This procedure represents a novel, convenient, and fairly general method for preparing y-aryl-/3-diketones. By this method the submitters have phenylated the dianion of 1-phenyl-1,3-butanedione (61%), 2,4-heptanedione (98%), 2,4-nonanedione (78%), 2,4-tridecanedione (53%), and 3,5-heptanedione (50%).6 Substituted diaryliodonium salts have also been used to produce l-(4-chlorophenyl)-2,4-pentadione (44%), 4-(4-methyl-phenyl)-l-phenyl-l,3-butanedione (44%), and l-(4-methyl-phenyl)-2,4-nonanedione (21%).6 Under these conditions no more than a trace, if any, of arylation at the a-position of the /3-diketones was observed by gas chromatography analysis. 

The cycloaddition reactions of the unsymmetrical a-diazo-/3-diketone, 2-diazo-l-phenyl-l,3-butanedione 330, with diaryl imines 331 took place with high regioselectivity, affording exclusively the 6-methyl-5-phenyl-substituted 477-l,3-oxazin-4-ones 332 via the acetylphenylketene, generated by the thermal Wolff rearrangement of 330 (Equation 32) <2002HAC165>. 

Certain other 1,3-dicarbonyl chelates were brominated with difficulty or not at all. For example, the trifluoro- and hexafluoroacetylacetonates (VI, R = CF3, R = CH3, and R = R = CF3) were not brominated under a variety of vigorous conditions. However, in the case of the chromium chelates of 1-phenyl-1,3-butanedione and dibenzoylmethane (VI, R = C( Hr), R = CH5, and R = R = C(iHr)), reaction with N-bromosuccinimide (NBS) was successful. That the electron density at the central carbon of the chelate ring is an important factor in the success or failure of these electrophilic substitutions is evident from the fact that the bis-(ethylenediamine)-2,4-pentanedionocobalt(III) cation cannot be brominated even under vigorous conditions. 

Phenylbiguanide [102-02-3] M 177.2, m 144-146°. Crystd from water or toluene. Phenyl boric acid (benzeneboronic acid) see Chapter 4. l-Phenyl-l,3-butanedione see benzoylacetone. 

Phenyl-1,3-butanedione, b64 4-Phenyk < c-butyl acetate, m361 Phenyl Cellosolve, p72 Phenyl chloride, c41... 

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