Structure and Properties of 2,2-Dibromovinyl Trifluoromethyl Ketone

Bozhenkov, G. V.; Frolov, Yu. L.; Toryashinova, D. S. D.; Levkovskaya, G. G.; Мирскова, А. Н.

doi:10.1023/b:rujo.0000003156.65761.7b

Cited by 13 publications

(5 citation statements)

References 2 publications

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“…Presumably, this isomerization was caused by a trace amount of bromine in the products. Alternatively, a similar isomerization was found to occur by photolysis at 254 nm for 1 h (Scheme ). − …”

Section: Synthesis Of Gem-dihalovinyl Systemsmentioning

confidence: 91%

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Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

2011

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Vinyl halides 24 and 25 were prepared from the tribromoromethyl carbinol 23, obtained in turn by reaction of benzo[b]thiophene-2-carboxaldehyde with the tribromomethane anion 43 generated in situ from 2,2,2-tribromoethanoic acid in DMSO (Scheme 24). 44 The intermediate 23 was treated with SOCl 2 or Et 2 NSF 3 to give the vinyl halides 24 (33% yield) or 25 (32% yield) through halogenation followed by dehydrobromination.2.1.3. Substitution Reactions. Although the most common source for gem-dibromoalkenes are carbonyl compounds, there are some examples in which alkene and alkyne derivatives have been used as starting materials. Reaction of longifolene 26 and camphene 29 with Hg(OAc) 2 /NaCl resulted in the isolation of vinylic dimercurichlorides 27 and 30, respectively (Scheme 25). These organometallics by treatment with Br 2 in pyridine afforded the related gem-dibromoalkenes 28 and 31 in very high yields. 45 Recently, 1,1-dibromo-2-arylethenes have been readily obtained in good yields (66À90%) via double ipso-bromo desilylation with N-bromosuccinimide (NBS) of 1,1-bis(trimethylsilyl)-2arylethenes, which were in turn easily obtained in high yields by Heck coupling of aryliodides with ethene-1,1-diylbis(trimethylsilane) (Scheme 26). 46 Interestingly, 1,1-bis(trimethylsilyl)-2-alkenylethenes, for example, 1,1-bis(trimethylsilyl)-4-phenylbuta-1,3-diene, under the same reaction conditions led to the selective formation of the dibrominated products containing 1,3-diene fragments.A variety of gem-dibromides were prepared from stannyl acetylenes (Scheme 27). These compounds by treatment with 1.4 equiv of Cp 2 Zr(H)Cl generated the related 1,1-heterobimetallic species of tin and zirconium, which by brominolysis with 2.5 equiv of Br 2 in CCl 4 or 3.0 equiv of N-bromosuccinimide at room temperature gave the corresponding dibromides in 53À83% yields. 47 2.1.4. Miscellaneous Reactions. Nenajdenko and co-workers reported an efficient one-pot transformation of a wide range of aldehydes and ketones into the corresponding dibromoalkenes via intermediate formation of the related hydrazones (Scheme 28). 48 Thus, these carbonyl compounds were treated with hydrazine hydrate, and when the starting materials disappeared, CBr 4 and catalytic CuCl were added to give the target products in 43À97% yields from aldehydes 48a and 43À97% yields from linear, cyclic, and caged ketones, 48a depending on the steric hindrance of the staring material. Analogously, a wide range of hydrazones of (hetero)aryl alkyl ketones (electron-rich and electron-poor) was converted into the related dibromoalkenes in 23À92% yields. 48b The proposed mechanism of the reaction starts from the oxidation of CuCl with CBr 4 to give a Cu(II) salt, which in turn oxidizes the hydrazone to the diazoalkane (Scheme 28). Decomposition of the diazoalkane generates a copperÀcarbene complex, which by interaction with CBr 4 finally leads to the dibromoalkene.

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Section: Synthesis Of Gem-dihalovinyl Systemsmentioning

confidence: 91%

“…The synthesis and a study of the chemical properties of 2,2-dibromovinyl trifluoromethyl ketone have been reported . This compound was prepared in 75% yield by trifluoroacetylation of 1,1-dichloroethene in the presence of aluminum bromide (Scheme ).…”

Section: Synthesis Of Gem-dihalovinyl Systemsmentioning

confidence: 99%

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

2011

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“…Table provides a nonexhaustive list of examples. As mentioned in Scheme , condensation of methyl hydrazine, depicted in many entries of this table, was found to be somewhat less efficient , than the use of N,N -dimethylhydrazine to prepare the 5-halogenopyrazoles. Interestingly, from β,β-fluoroenones, small amounts of the alternative isomers B were obtained with some alkylhydrazines at room temperature (Table , entries 3 and 4).…”

Section: Rearrangements Cycloadditions and Condensationsmentioning

confidence: 94%

“…The ease of dealkylation of such pyrazolium intermediates is also apparent in the 5-chloropyrazole 200 arising from treatment of antipyrine ( 198 ) with phosphorus oxychloride. Interestingly, the 4-phosphorylated side product 201 along with a 4-chloro homologue 202 were also isolated. , Although this synthetic method was further described above, another proof of the lability of alkyl pyrazolium is the result of the room-temperature condensation between β,β-dibromoenone 203 and two equivalents of 1,1-dimethylhydrazine 204 , which gave a good yield of the 3-trifluoromethylpyrazole 205 along with the hydrazinium salt 206 . , …”

Section: Modifications Of 3/5-halogenopyrazolesmentioning

confidence: 99%

Preparation and Chemistry of 3/5-Halogenopyrazoles

Janin

2012

Chem. Rev.

169

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3924 2. Electrophilic Halogenations 3925 2.1. Electrophilic Halogenation of Pyrazoles 3925 2.2. Halogenation of Pyrazole Anions 3929 3. Preparations from 3/5-Hydroxy-or 3/5-Aminopyrazoles 3930 3.1. Dehydroxyhalogenation of 3/5-Hydroxypyrazoles 3930 3.2. Halogenodediazoniation of 3/5-Aminopyrazoles 3934 4. Rearrangements, Cycloadditions, and Condensations 3936 4.1. Rearrangement of Pyrazole N-Oxides 3936 4.2. Cycloadditions 3937 4.3. Condensations 3938 5. Modifications of 3/5-Halogenopyrazoles 3940 6. Miscellaneous 3943 7. Chemistry of Halogenopyrazoles 3944 7.1. Chemistry of 4-Halogenoyrazoles 3944 7.1. Chemistry of 3/5-Halopyrazoles and Activated Esters of Hydroxypyrazoles 3947 7.3. CH Activation of Pyrazoles 3949 8. Conclusion 3951 Author Information 3951 Corresponding Author 3951 Notes 3951 Biography 3951 Acknowledgments 3951 References 3951

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“…Further elution gave 3,3-dichloro-1-phenylprop-2-en-1-one 9 (0.024 g, 12%) as colorless liquid. 1 H NMR (300 MHz, CDCl 3 ) δ 7.93 (d, J = 7.2 Hz, 2H), 7.61 (t, J = 7.2 Hz, 1H), 7.50 (t, J = 7.2 Hz, 2H), 7.27 (s, 1H) ppm; 13 C NMR (75.5 MHz, CDCl 3 ) δ 186.7, 136.9, 135.5, 133.7, 128.8, 128.5, 124.0 ppm; IR (KBr) ν max 3059(m), 1671(s), 1568(s), 1449(m), 1265(m), 1221 (s), 1015(m), 938(m), 841(m), 788(m), 695(m), 628(m) cm –1 .…”

Section: Experimental Sectionmentioning

confidence: 99%

Synthesis of α-Functionalized Trichloromethylcarbinols

Ram

Soni

2015

J. Org. Chem.

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A new series of α-functionalized trichloromethylcarbinols have been synthesized from corresponding α-halomethyl ketones, esters, and amides in 48-78% overall yields. Reactivity of nitrates obtained in the first step was dependent on the electron-withdrawing nature of the functional groups, and increases with increasing electron deficiency. Synthetic applications of such trichloromethylcarbinols for the preparation of chloromethyl-α-diketones, trichloromethylated dihydrofurans, and enol acetates of α-functionalized acid chlorides have been demonstrated. The reaction of these compounds in the Jocic-Reeve reaction was also demonstrated.

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Structure and Properties of 2,2-Dibromovinyl Trifluoromethyl Ketone

Cited by 13 publications

References 2 publications

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

Preparation and Chemistry of 3/5-Halogenopyrazoles

Synthesis of α-Functionalized Trichloromethylcarbinols

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