A-Acetonaphthone

Table 10.8. Effect of Temperature on the Product Distribution from the a-Acetonaphthone-Sensitized Photoaddition of Cyclopentadiene to cis- and trans-Dichloroethylene<60>...

The photo-Diels-Alder reaction of a-acetonaphthone 145 with the chiral a-enaminonitrile 146 yielded the cycloadduct 147 with almost complete diastere-oselectivity (Scheme 37) [91,92]. The intermediately formed biradical R is particularly stable owing to delocalization of the radical on the aromatic moiety and to a captodative effect on the enamine moiety. In analogy to the Paterno-Btichi reaction (see Scheme 7), the chiral induction occurred in two steps. In the first step, a chiral center is created at the a-position of the acyl group. In the second step of the diastereoselection, one of the two diasteromeric intermediates undergoes preferential cyclization to yield the final product 147, while the other one is decomposed to form the starting material [92]. 

Methyl 2-naphthyl ketone. See 2 -Acetonaphthone Methyl a-naphthyl ketone CAS 941-98-0 EINECS/ELINCS 213-384-1 Synonyms 1-Acetonaphthalene 1-Acetonaphthone 1 -Acetonaphthone a-Acetonaphthone 1 -Acetyl naphthalene a-AcetyInpahthalene Ethanone, 1-(1-naphthalenyl)- Methyl 1-naphthyl ketone o-... 

Irradiation of a mixture of hexadiene isomers in 1,1-dichloroethylene with /J-acetonaphthone gave four cyclobutane derivatives<54) ... 

The decomposition of methanesulphonyl azide in isopropyl alcohol could be effected by selective irradiation of 2-acetonaphthone instead of benzophenone 21>. Since 2-acetonaphthone triplets are incapable of hydrogen abstraction from isopropyl alcohol 22>, initiation must occur via transfer of excitation energy to the azide. A marked difference was observed from benzophenone sensitization in that the reaction was extremely slow, gave a nitrogen yield of only 68%, and produced a yellow solution 21>. 

The photoreductions of a number of carbonyl compounds with either lowest mr or jiji triplet states in the presence of tributyltinhydride are reported24. The carbonyl compounds include cyclohexanone and acetone which possess nrr lowest-energy triplets, and 2-acetonaphthone, 1-naphthaldehyde and 2-naphthaldehyde which possess lowest-energy mr triplets. In the case of the two njr triplets, a simple mechanism is proposed which involves the abstraction of a hydrogen atom from the tributyltinhydride by the triplet state... 

Immobilized catalysts on solid supports inherently have benefits because of their easy separation from the products and the possibility of recycling. They are also expected to be useful for combinatorial chemistry and high-throughput experimentation. The polystyrene-bound BINAP/DPEN-Ru complex (beads) in the presence of (CH3)3COK catalyzes the hydrogenation of l -acetonaphthone with an SCR of 12 300 in a 2-propanol-DMF mixture (1 1, v/v) to afford the chiral alcohol in 97% ee (Fig. 32.35) [113]. This supported complex is separable... 

Fig. 32.50 Hydrogenation of 1-acetonaphthone with a DM-BI-PHEP/(S,S)-DPEN-Ru catalyst.

For example, the hydrogenation of 1-acetonaphthone with a catalyst system consisting of RuCl2[(X)-BINAP](DMF)n, (S.S)-1.2-diphenylethylenediamine... 

Electrochemistry offers new routes to the production of several commercially relevant a-arylpropionic acids, used as non-steroidal anti-inflammatory agents (NSAI) [178,182]. A preparative method based on sacrificial Al-electrodes has been set up for the electrocarboxylation of ketones [117,183-187] and successfully applied to the electrocarboxylation of aldehydes, which failed with conventional systems. The electrocarboxylation of 6-methoxy-acetonaphthone to 2-hydroxy-2-(6-methoxynaphthyl)propionic acid, followed by chemical hydrogenation to 2-(6-methoxynaphthyl)-2-propionic acid - one of the most active NSAI acids - has been developed up to the pilot stage [184,186],... 

The photocyanation of 1-nitroazulene was accompanied by a dark reaction and was thus less suitable for mechanistic studies than the methoxylation. 2-Acetonaphthone (Et=59 kcal mole i) and 2-naphthophenone ( t=60 kcal mole i) were found to be efficient sensitizers for the disappearance of 1-nitro azrdene in the methoxylation reaction. The measured rate of product formation, however, seemed to be much lower than the rate of starting material disappearance. This effect has been attributed to sensitized decomposition of the product 104)... 

Remarkable positive shifts of the °red values of the singlet excited states of the metal ion-carbonyl complexes as compared to those of the triplet excited states of uncomplexed carbonyl compounds (Table 2) result in a significant increase in the redox reactivity of the Lewis acid complexes versus uncomplexed carbonyl compounds in the photoinduced electron-transfer reactions. For example, photoaddition of benzyltrimethylsilane with naphthaldehydes and acetonaphthones proceeds efficiently in the presence of Mg(C104)2 in MeCN, although... 

Lead tetraacetate oxidative cyclization of the A-(l-naphthylvinyl)urethane 30, derived from I -acetonaphthone 28, yields 4-naphthyl-2(3//)-oxazolone 32 as the... 

The remaining compounds possess it,it emitting triplets in all media used (Group III). The members of this class are 1,2-diphenylacetone, o-methoxy-acetophenone, xanthone, and 2 -acetonaphthone. This group is characterized by a long-lived phosphorescence in all solvents and by a decrease in the energy of the emitting triplet upon increased solvent polarity. 

With the chiral diamine (S,S)-20 as a co-catalyst full conversion was obtained in all cases, indicating that the amine has a pronounced influence on reactivity and selectivity (entries 9-14). The combination (R Rc)-4ael/(S,S)-20 afforded 18a as an almost racemic mixture (entry 9). The value of 6% ee (R) obtained in this experiment reflects two opposite contributions. On one hand, the system chiral phosphorous ligand/achiral diamine (R Rc)-4ael/19 led to 18a with 65% ee (S) (entry 1). On the other hand, an ee value of 75% (R) in the hydrogenation of 1-acetonaphthone has been reported for the system achiral phosphine (PPh3)/(S,S)-20 [41] This indicates that two inductions are canceled in an almost additive way in the mixed system. 

Evidence very recently presented by O Farrell ei ah [3J indicates that the preferred conformation (XIII) of 2 hydroxy-5,6,7,8-tetra-hydro- 1-acetonaphthone is that which is unfavourable for chelation. However, this is not necessarily inconsistent with our views. Certainly XIII is in equilibrium with that conformation (XIV) which is favourable for chelation. Our argument merely postulates that chelation in a conformation like XIV is favoured by the bulk of the methylene group in the alicyclic ring. 

Tetrahydro-1- acetonaphthone—Methylmagnesium bromide, prepared in ether from 5-11 g of magnesium, was treated with 18-5 g of cadmium chloride. The mixture was refluxed for 1 hour and the ether replaced by 150 ml of benzene. A solution of 5-0 g (0-026 mole) of... 

Hydroxy-5,6,7,8-tetrahydro-2-acetonaphthone [3].—On mixing 32 1 g of aluminium chloride with 35 0 g (0 184 mole) of 5,6,7,8-tetrahydro-2-napbthyl acetate [10] a vigorous reaction occurred immediately, and hydrogen chloride was evolved rapidly. After the initial reaction had subsided, the mixture was heated for 0 5 hour at 130°. The tan solid obtained on decomposition of the cooled mixture... 

Quantum yields for photoreduction of 1-naphthaldehyde, 2-acetonaphthone,370 and p-phenylbenzophenone365,366 in 2-propanol are all 0.1 or lower, as compared with a limiting value of 2 for benzo-phenone. Since the triplets of the first three compounds undoubtedly possess a 77,77 configuration366,370 and a hundredfold longer lifetime... 

Since acetonaphthones have 7r,7r configurations in their lowest triplet states, it seems probable that l-benzoyl-2-methylnaphthalene, 30, would also. As suspected, 30 does not undergo photoenolization.362 However, 6-benzoylbenzanthrone, 31, which would also be expected to possess a low-lying triplet, does form a photoenol, as determined by formation of yellow coloration at low temperatures and deuterium exchange at the benzylic position. It is entirely possible that the greater reactivity of the benzyhydryl C—H bond in 31 allows reaction even in a relatively unreactive state, or in an n,tt singlet. 

Figure 7 Tautomers of Schiff bases derived from /J-diketone (a-c), from l-hydroxy-2-acetonaphthone (d, e) and from...

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