- PERI-METHANOARENES BY THERMOLYSIS OF TRIMETHYLSILANES
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Practical syntheses of varied peri-methanoarenes have been developed.
- Engler, T. A.,Shechter, H.
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- Pd-catalyzed allylative dearomatisation using Grignard reagents
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Pd-catalyzed allylative dearomatisation of naphthyl halides is shown to be feasible by employing Grignard reagents. The high reactivity of the nucleophile allows for fast reactions and low catalyst loading, while a plethora of successfully substituted compounds illustrate the broad scope. Five membered heteroaromatic compounds are also demonstrated to be reactive under similar conditions.
- Boldrini, Cosimo,Harutyunyan, Syuzanna R.
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supporting information
p. 11807 - 11810
(2021/11/30)
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- Regioselective reductive opening of substituted phthalans: synthetic applications
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The reductive opening of substituted phthalans 6, 11, 12, 20, 21 and 28 with lithium and a catalytic amount of DTBB leads to the formation of corresponding functionalised organolithium intermediates 8, 15, 16, 23, 25 and 29+30 in a regioselective manner. The further reaction of these dianions with different electrophiles, mainly carbonyl compounds, gives the expected functionalised benzylic alcohols 9, 17, 18, 24, 26 and 31+32. The observed stereochemistry can be easily explained taking into account the values of the electron densities deduced by semiempirical PM3 calculations.
- García, Daniel,Foubelo, Francisco,Yus, Miguel
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p. 4275 - 4286
(2008/09/20)
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- Regiochemistry in the reductive opening of phthalan derivatives
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The lithiation of phthalan derivatives 4, 9 and 12 with an excess of lithium in the presence of a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB) in THF at -78 °C gives dianionic intermediates 5, 10 and 13, respectively, which by reaction with different electrophiles [H2O, t-BuCHO, Me2CO, (EtO)2CO] at the same temperature, followed by hydrolysis, leads to regioselective functionalised naphthalenes 7, and biphenyls 11 and 14. The reductive opening takes place with high or total regioselectivity and can be explained considering the electron density in the dianion or in the radical anion, which are formed previous to the carbon-oxygen bond excision. The lithiation of the dihydrofurophthalan derivative 18 with the same reaction mixture but at higher temperature (0 °C) leads to intermediates 19 and 20, resulting from a single and a double reductive cleavage, respectively, which after addition of H2O and benzaldehyde as electrophiles gives a mixture of compounds 21 and 22.
- Foubelo, Francisco,García, Daniel,Moreno, Benjamín,Yus, Miguel
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p. 3379 - 3383
(2008/02/12)
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- Facile reductive coupling of benzylic halides with ferrous oxalate dihydrate
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Facile reductive coupling of benzylic halides is reported with ferrous oxalate dihydrate in DMF or HMPA under nitrogen atmosphere at 155-160°C. The coupling is proposed to proceed by two successive oxidative additions of benzylic halides to ferrous oxalate to give an intermediate organoiron complex which undergoes concerted dimerization to give the corresponding reductively coupled dimers in high yields.
- Khurana, Jitender M.,Chauhan, Sushma,Maikap, Golak C.
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p. 1737 - 1740
(2007/10/03)
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- Dearomatizing Annelation of Five-Membered Rings to Naphthalenes by Organolithium Cyclization
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γ-Lithiopropylnaphthalenes and their oxa- and aza-tethered analogues cyclize by nucleophilic addition of the organolithium to the naphthalene ring. The resulting benzyllithiums react stereoselectively with electrophiles to give dearomatized tricyclic prod
- Clayden, Jonathan,Kenworthy, Martin N.
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p. 787 - 790
(2007/10/03)
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- Synthesis and Autoxidation of 2,3,4-Trimethylnaphthalen-1-ol and Related Naphthalen-1-ols
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The oxidation of 2-methylnaphthalene, 1,2-dimethylnaphthalene, 2,3-dimethylnaphthalene, and 1,2,3-trimethylnaphthalene by lead tetraacetate in dichloroacetic acid and chloroform gave fair to low yields of the dichloroacetyl derivatives of 2-methylnaphthalen-1-ol, 3,4-dimethylnaphthalen-1-ol, 2,3-dimethylnaphthalen-1-ol, and 2,3,4-trimethylnaphthalen-1-ol respectively.In the case of 1,3-dimethylnaphthalene, dichloroacetoxylation was not observed, and the only isolated product was the binaphthyl (10). 2,3,4-Trimethylnapthalen-1-ol, obtained on hydrolysis of the dichloroac etyl derivative, was very sensitive to oxygen even in the solid state, and when shaken in chloroform in an oxygen atmosphere gave 4-hydroperoxy-2,3,4-trimethylnaphthalen-1-(4H)-one (14).A study of the autoxidation of the naphthalen-1-ols (7), (19) and (20) led to the conclusion that the oxygen-sensitivity of (11) resulted from a 4,5 peri interaction.
- Greenland, Harry,Pinhey, John T.,Sternhell, Sever
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p. 325 - 331
(2007/10/02)
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