3-bromo-4-fluoro-benzaldehyde

Acetals of 3-bromo-4-fluoro benzaldehydes have been successfully subjected to the Ullmann reaction with several phenolates and anilines, leaving the fluorine untouched, producing the following intermediates ... 

Benzaldehyde, 4-ethoxy-3-methoxy-, 56, 44 Benzaldehyde, 4-ethoxy-3-methoxy-, ethylene acetal, 56, 44 Benzaldehyde, 4-isopropyl-, 55,10 Benz[e ] anthracene, 58, 15, 16 BENZENAMINE, 4-bromo-Ar, V-dimcthyl-3-(tnfluoromethyl)-, 55, 20 Benzene, bromo-, 55,51 Benzene, 1 bromo-4-chloro-,55, 51 Benzene, 4-bromo-l, 2-dimethyl, 55, 51 Benzene, l-bromo-4-fluoro-, 55, 51 Benzene, 1 -bromo-4-methoxy-, 55,51 Benzene, l-bromo-3-methyl-, 55, 51 Benzene, 4-(cr/-buty 1-1-ethyl, 55, 10 Benzene, chemical hazard warning, 58, 168 Benzene, chloro-,56, 86 Benzene, l-ethyl-4-isopropyl-, 55, 10... 

This method of preparation of a halobenzaldehyde is of wide application and has been used for the preparation of the following substituted benzaldehydes 2-bromo-5-methyl-,4 2,3-dichloro-and 2,4-dichloro-,5 2-chloro-4-methyl-,-iodo-, />-fluoro-, 2-iodo-4-methyl-, and 6-iodo-3-methyl-.9... 

C8H4F40 2-fluoro-6-(trifluoromethyl)benzaldehyde 60611-24-7 428.65 37.073 1.2 12730 C8H6BrN a-bromo-p-tolunitrile 17201-43-3 501.65 44.043 2... 

C8H4F40 4-fluoro-3-(trifluoromethyl)benzaldehyde 67515-60-0 451.15 39.211 1,2 12731 C8H6BrN a-bromo-o-tolunitrile 22115-41-9 501.65 44.043 2... 

C8H4F40 2-fluoro-4-(trifluoromethyl)benzaldehyde 89763-93-9 391.65 33.579 1,2 12732 C8H6BrN a-bromo-m-tolunitrile 28188-41-2 501.65 44.043 2... 

In contrast, the synthesis of cycloproparenes monosubstituted at Cl by this route failed. For example, pyrolysis of the adduct derived from ll-niethyl-1,6-methano[10]annulene resulted in formation of styrene, while that from the 11-bromo and 11-cyano derivatives gave only polymeric material. Similarly, only benzaldehyde was isolated upon pyrolysis of the adduct 2 of ll-fluoro-l,6-methano[10]annulenc with acetylenedicarboxylate. Benzaldehyde is the expected hydrolysis product of 1-fluorobenzocyclopropene. 

Kotsuki and co-workers used amidines to synthesize 2-substituted quinazolines. Reaction of 2-fluoro-5-nitro-benzaldehyde with 4-bromo-benzyl amidine gave the corresponding quinazoline in modest yield. This approach was subsequently used by Kotsuki and co-workers to generate a number of 5-nitro- and 5-cyanoquinazolines in modest yields. 

At the same time as discussed in [82], Cheng and coworkers [83] reported the Rh-catalyzed oxidative C-H-activated annulation of benzaldehydes with alkynes to form indenones. In this approach, an acetylhydrazone was formed in situ using acetylhydrazine and acetic acid. Subsequently, the in situ DG removal takes place since ketone hydrazone is more susceptible toward hydrolysis than aldehyde hydrazone. The procedure tolerates a series of functional groups, such as methoxyl, acetylamino, fluoro, trifluoromethyl, methoxycarbonyl, chloro, and bromo groups. 

Fluorodecarboxylation was also used for the introduction of fluorine into the furan ring. Thus, treatment of 29 with Selectfluor afforded 3-bromo-2-fluorofuran 30. Subsequent transmetallation with nBuLi and quench with benzaldehyde furnished alcohol 31 in 21 % overall yield. Similarly, 5-hromo-2-furoic acid 32 was transformed into 2-bromo-5-fluorofuran 33 and then to 2-benzoyl-5-fluorofuran [28] and 5-fluoro-2-furoic acid 34 [29]. 

Reaction of carbene, generated from PhHgCBrjF, with benzaldehyde and dimethyl acetylenedicarboxylate afforded 2-bromo-2-fluoro-2,3-dihydrofuran 63. The compound 63 was aromatized by treatment with sodium methoxide producing fluorofuran 64. The reaction proceeded via intermediate carbonyl yUde that was trapped with dimethyl acetylenedicarboxylate in the subsequent [3+2] cycloaddition reaction [45]. 

In the chromium-mediated reaction of 1-fluoro-l-bromo-l-alkene with an aldehyde, the ( )-isomer reacts more quickly than the (Z)-isomer. Therefore, when a mixture of stereoisomer 42a was subjected to the reaction with benzaldehyde in the presence of CrCl2 and Ni catalyst, a (Z)-isomer of allylic alcohol 51 was selectively formed [77, 78] (Scheme 21). The reaction proceeds through an alkenylchromium species 52, and the formation of the ( )-alkenylchromium species is much faster than that of the (Z)-isomer. Actually, the reactimi of a pure (Z)-isomer of 1 -fluoro-1 -bromo-1-alkene with aldehyde is sluggish, and the corresponding ( )-isomer of the product was obtained in low yield or not obtained at all. Therefore, a good method for the synthesis of ( )-51 has not yet been reported. 

Asymmetric Aldol Reaction of Bromofluoroketene Silyl Acetal 2 Catalyzed by Lewis Acids 6. We next examined the aldol reaction of the bromofluoroketene silyl acetal 2 mediated by the catalyst 6 (30). The reaction was carried out by the addition of an aldehyde in nitroethane to a solution of 1.2 equivalents of the acetal 2 and 20 mol% of the catalyst 6 in the same solvent over 3 h at -7S°C and stirring at that temperature for an additional hour prior to quenching. As shown in Table II, the reaction of benzaldehyde afforded a 69 31 mixture of (2S,31 )- and (2R,3/ )-2-bromo 2-fluoro-3-hydroxy-3-phenylpropanoates. The enantiomeric excess of fte syn-isomer is 98% ee and diat of die an/i-isomer is 90% ee (entry 1). Although die reactions are not diastereoselective in all cases (synlanti = 69/31 to 46/54), aU syn- and anri-aldol products were obtained with excellent-to good chemical and optical yields. 

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