Trans-4-phenyl-3-buten-2-one

Ordinary Grignard reagents react with a, -unsaturated carbonyl compounds and afford both 1,2-adduct and 1,4-adduct. However, methylsulfonyhnethylmagnesium bromide or p-tolylsulfonylmethylmagnesium bromide gave only 1,2-adducts in the reaction with conjugated carbonyl compounds such as crotonaldehyde, cinnamaldehyde, trans-4-phenyl-3-buten-2-one, benzalacetophenone and l,5-diphenyl-2,4-pentadien-l-one. 

Typical reactions in this category occur with 1-chloro-2,4-dinitrobenzene, 1,2-chloro-4-nitrobenzene, ethacrynic acid, trans-4-phenyl-3-buten-2-one and a range of hydroxylated derivatives of polycyclic hydrocarbons. 

A 500-mL, three-necked, round-bottomed Mask is equipped with a mechanical stirrer, nitrogen inlet adapter, and 150-mL pressure-equalizing dropping funnel fitted with a rubber septum (Note 1). The flask is charged with 70 mL of dry tetrahydrofuran (Note 2) and 15.9 mL (0.075 mol) of 1,1,1,3,3,3-hexamethyldisilazane (Note 3), and then cooled in an ice-water bath while 28.8 mL (0.072 mol) of a 2.50 M solution of n-butyllithium in hexane (Note 4) is added dropwise over 5-10 min. After 10 min, the resulting solution is cooled at -78°C in a dry ice-acetone bath, and a solution of 10.0 g (0.068 mol) of trans-4-phenyl-3-buten-2-one (Note 5) in 70 mL of dry tetrahydrofuran is added dropwise over 25 min. The dropping funnel is washed with two 5-mL portions... 

C10H9NO2 methyl indole-3-carboxylate 942-24-5 25.00 1 2355 2 19104 C10H10O trans-4-phenyl-3-buten-2-one 1896-62-4 45.00 1.0097 1... 

Phenylbutenone 4-Phenyl-3-buten-2-one trans-4-Phenyl-3-buten-2-one Styryl methyl ketone... 

Among the a,p-unsaturated ketones, only the trans-4-phenyl-3-buten-2-one affords the excellent induction (Eq. 26.7). The product alcohols have the (S)- configuration (Table 26.10) [3, 5]. 

Nolen et al. also reported the self-condensation reaction of butyraldehyde and the cross-aldol condensation of benzaldehyde with acetone (Figs. 9.58 and 9.59) at 250°C. The butyraldehyde self-condensation produced a number of products, including 2-ethyl-2-hexenal, 2-butyl-2-butenal, and 2-ethyUiexanal. The results from the condensation of butyraldehyde indicate that a 40% yield of 2 -ethyl-2 -hexenal is achieved before the formation of by-products becomes dominant. In addition, investigations of the back reaction show that a substantial quantity of butyraldehyde is formed when 2-ethyl-2-hexenal is subjected to water at 250°C. The condensation reaction of benzaldehyde with acetone produced a 15% yield of trans-4-phenyl-3-buten-2-one in 5 h and very small quantities of trans,trans-dibenzylidene acetone during this same period of time. The authors suggest that the low yield could be a result of equilibrium limitations. 

Table 3 summarizes the scope and limitation of substrates for this hydrogenation. Complex 5 acts as a highly effective catalyst for functionalized olefins with unprotected amines (the order of activity tertiary > secondary primary), ethers, esters, fluorinated aryl groups, and others [27, 30]. However, in contrast to the reduction of a,p-unsaturated esters decomposition of 5 was observed when a,p-unsaturated ketones (e.g., trans-chalcone, trans-4-hexen-3-one, tra s-4-phenyl-3-buten-2-one, 2-cyclohexanone, carvone) were used (Fig. 3) [30],... 

The disilanickela complex 21 was also found to be a good catalyst for the dehydrogenative double silylation of aldehydes. The nickel-catalyzed reactions of 1,2-bis(dimethylsilyl)carborane 11 with aldehydes such as isobutyraldehyde, trimethylacetaldehyde, hexanal, and benzaldehyde afforded 5,6-carboranylene-2-oxa-l,4-disilacyclohexane.32 34 36 The dehydrogenative 1,4-double silylation of methacrolein and tram-4-phenyl-3-buten-2-one in the presence of a catalytic amount ofNi(PEt3)4 also took place under similar conditions. In contrast, the reaction of 11 with a-methyl-tran.s-cinnamaldehyde and irans-cinnamaldehyde under... 

Use of aluminum-based bidentate Lewis acid 14 results in unique stereoselectivity in the Michael addition of KSA (Scheme 10.84) [37[. The 14-promoted reaction of the KSA derived from mefhyl isobutyrate wifh 4-phenyl-3-buten-2-one gives fhe corresponding E adduct selectively, in contrast wifh fhe 15-promoted reaction, which is Z-selective. The origin of fhe inverse selectivity is probably that 14 forces the enone to take fhe s-trans formation 92 by double coordination of the carbonyl oxygen. 

Substrates GSTM1 -1—Trans-stilbene oxide, DCNB-high, CDNB-mod-erate, Aflatoxin Bl-exo 8,9-epoxide, androstene 3,17-dione, B(a)P-diol epoxide, B(fl)P-4,5-oxide, chrysene diol epoxide, cumene hydroperoxide, ethacrynic acid, -nitrophenyl acetate, PGA2, PGJ2, styrene 7,8-oxide, fran5-4-phenyl-3-buten-2-one. 

The combination of the three-component domino Knoevenagel/Diels-Alder/epimerization allowed the construction of structures that with suitable modification gave the natural product-like cores as reported in a work of 2007 [87]. Hence, 1,3-dicarbonyl compounds 182 with benzaldehydes 4 and ( )-4-phenyl-3-buten-2-one 183 in the presence of a catalytic amount of (5)-5,5-dimethyl thiazoli-dinium-4-carboxylate 184 produced corresponding spiro compounds 185 in good yields (50-80%) and high diastere-oselectivity [dr (cis/trans) >99 1] (Scheme 2.61). 

---