Vinyl phenyl ketone

Frequently B will also undergo a back hydrogen transfer which regenerates the parent ketone, as well as cyclization (in most cases a minor reaction) as a result of this competition the quantum yields of fragmentation are typically in the 0.1-0.5 range in non-polar media. When the Norrish Type II process takes place in a polymer it can result in the cleavage of the polymer backbone. Poly(phenyl vinyl ketone) has frequently been used as a model polymer in which this reaction is resonsible for its photodegradation, reaction 2. 

The results presented in this report correspond to systems where reactions 2 and 3 account for the decay of carbonyl triplets A series of copolymers of phenyl vinyl ketone and o-tolyl vinyl... 

Reaction of phenyl vinyl ketone with cyclopentanone under thermal conditions resulted in a diastereomeric mixture of 1,5,9-triketones 374 via a double Michael reaction. Treatment of this mixture with ammonium formate in polyethyleneglycol-200 under microwave irradiation conditions led to the very fast and efficient formation of a 2 1 diastereomeric mixture of cyclopental flquinolizidines 375 and 376 <2002T2189>. When this reductive amination-cyclization procedure was carried out starting from the purified /ra r-isomer of 374, the result was identical to that obtained from the cis-trans mixture, showing the operation of thermodynamic control (Scheme 86). 

With the CMR, phenyl vinyl ketone was prepared by passage of a 5% aqueous slurry of N-(2-benzoylethyl)-N,N,N-trimethylammonium iodide through the micro-wave zone. The product was immediately extracted from the cooled aqueous effluent into chilled Et20, avoiding polymerization of the monomer and giving near quantitative yields [22],... 

With conjugated enone substrates, the alkoxymetallation leads to the formation of a metal enolate that can undergo a facile protonation to accomplish the hydroalkoxylation. Following this mechanism, various /3-alkoxyketones were obtained in good yields by the addition of primary and secondary alcohols to methyl vinyl ketone under cationic Pd(n) catalysis.443 Similarly, [Rh(COD)(OMe)]2 was found to catalyze the hydroalkoxylation of both methyl vinyl ketone and phenyl vinyl ketone (Equation (121)).444... 

Table 22.3 Use of phenyl vinyl ketone (PVK) in intermolecular hydrogen-mediated reductive aldol coupling.

M. Shi and Y.-L. Shi reported the synthesis and application of new bifunctional axially chiral (thio) urea-phosphine organocatalysts in the asymmetric aza-Morita-Baylis-Hillman (MBH) reaction [176, 177] of N-sulfonated imines with methyl vinyl ketone (MVK), phenyl vinyl ketone (PVK), ethyl vinyl ketone (EVK) or acrolein [316]. The design of the catalyst structure is based on axially chiral BINOL-derived phosphines [317, 318] that have already been successfully utilized as bifunctional catalysts in asymmetric aza-MBH reactions. The formal replacement of the hydrogen-bonding phenol group with a (thio)urea functionality led to catalysts 166-168 (Figure 6.51). 

Rao, H.S.P., Jeyalakshmi, K. and Senthilkumar, S.P., Novel domino products from the reaction of phenyl vinyl ketone and its derivatives with cyclic ketones, Tetrahedron, 2002, 58, 2189-2199. 

Several groups have prepared cyclopentane systems by intramolecular Michael addition.72 Reaction of the triester (292 Scheme 37) with phenyl vinyl ketone (293) and base produces the cyclopentane (295) in good yield via an intermolecular (giving 294) and subsequent intramolecular Michael addition.72 When the Michael acceptor is a cyclohexenone (Scheme 38), the c/s-fused hydrindanone is produced (298 or 297).72b 72f Spiro systems can also be formed by these reactions (300a,b equation 66) in which the Michael addition gives a spiro ring fusion. 

Conversion of a Mannich base hydrochloride into an a,/ -unsaturated carbonyl compound, is illustrated by the formation of phenyl vinyl ketone, which is obtained directly by steam distillation (Expt 6.147). Alternatively the Mannich base may be treated with methyl iodide to form the quaternary salt, which then gives the a,/ -unsaturated carbonyl compound by a base-catalysed elimination reaction. 

The quaternary salts produced by the Mannich reaction undergo a number of conversions useful in synthesis. For example, although stable at room temperature they eliminate an amine hydrochloride on heating to yield an a,/J unsaturated ketone (e.g. the conversion of dimethylaminopropiophenone to phenyl vinyl ketone, Expt 6.147). 

Conversion to phenyl vinyl ketone. Place an intimate mixture of 21.4 g (0.1 mol) of //-dimethylaminopropiophenone hydrochloride and 0.2 g of hydroquinone in a 100-ml round-bottomed flask. Attach a Claisen still-head fitted with a stout capillary air leak and condenser arranged for distillation under reduced pressure place a few crystals of hydroquinone in the receiving flask. Pyrolyse the amine hydrochloride by heating the flask in an electric mantle at 2 mmHg (oil immersion pump), and collect the crude ketone which distils between 70 and 90 °C. On redistillation 7g (51%) of pure phenyl vinyl ketone, b.p. 72-73 °C/3 mmHg (115 °C/18 mmHg), are obtained. Characterise... 

The idea of ring-formation is supported by the pronounced steric effect observed for the addition of branched amines to phenyl vinyl ketone (28). The small value of the reaction constant q for m- and >-phenyl substituted p-morpholinopropiophenone (30) can be taken to indicate that the reaction centre is more distant from the phenyl ring. 

Variations have been made in the activated system also. Higher homologues of butenone (e.g., l-penten-3-one, tert-butyl vinyl ketone) react 1n the same manner, as does phenyl vinyl ketone. The same variety of functional groups as shown before may be possible in the side chain of the ketone... 

Ethyl acetoacetate Phenyl vinyl ketone Ethyl 2-acetyl-5-... 

The head-to-tail combination of conjugated enone units also was evident in the S-heterocyclic products obtained from phenyl vinyl ketone 14 when the latter was treated with alcoholic polysulfide. The product mixture contained the 2,4-dibenzoylthiolane ana the corresponding thiophene obtained in 5.8 and 3 % yields respectively. 

The condensation of 5-bromoisatin with methyl p-phenyl vinyl ketone in a water-benzene medium in the presence of sodium hydroxide and the phase-transfer catalyst Et4N Br takes place readily, and 6-bromo-2-(P-phenylvinyl)-4-quinolinecarboxylic acid is formed with an 85% yield [29],... 

Reactions of acyclic l-phenylsulfinyl-4-(alkoxycarbonyl)amino butadienes 143 with phenyl vinyl ketone and acrolein were studied by Overman et al. (Scheme 71) [119b]. Good reactivity and complete regioselectivity (controlled by the nitrogen moiety) were the main characteristics exhibited by these dienes. Additionally, the endo approaches are clearly favored with respect to the exo ones (endo/exo ratio is 10 for aldehyde and higher than 100 for ketone). Unfortunately, the 7r-facial selectivity was small or non-existent in both endo and exo approaches, yielding a 1 1 mixture of the two possible diastereoisomers (Scheme 71). 

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