- Brominative Deoxygenation of Some Aldehydes and Ethers
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Three aldehydes (4a-c) are transformed into 1,1-dibromides (6a-c) by 2,2,2-tribromo-2,2-dihydro-1,3,2-benzodioxaphosphole (2).This reagent (2) is also very active in the cleavage of ethers; its reactions may show some features of carbonium as well as of SN2 character.
- Roman, Ulrich von,Knorr, Rudolf,Behringer, Claudia,Ruhdorfer, Jakob
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p. 260 - 262
(2007/10/02)
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- Synthesis of 1,1-Dihaloalkanes
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The reaction of 1,1-bistrifluoromethylsulfonyloxy-alkanes (2) with magnesium iodide in carbon disulphide at O deg C affords 1,1-diiodoalkanes (3-I) in good yields.No rearrangement products are observed.The reaction of 2 with magnesium bromide in carbon disulphide or titanium tetrachloride in dichloromethane yields either 1,1-dichloro- (3-Cl) or 1,1-dibromoalkanes (3-Br).Rearrangements products are formed from α-branched substrates.
- Garcia Martinez, A.,Herrera Fernandez, A.,Martinez Alvarez, R.,Garcia Fraile, A.,Bueno Calderon, J.,et al.
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p. 1076 - 1078
(2007/10/02)
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- Bromochlorination of Alkenes with Dichlorobromate (1-) ion. IV. Regiochemistry of Bromochlorinations of Alkenes with Molecular Bromine Chloride and Dichlorobromate (1-) Ion
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The regioselectivity of the addition of molecular bromine chloride to alkenes is dependent on both the steric and electronic effects of the alkyl substituent.In contrast, the regioselectivity of the addition of dichlorobromate (1-) ion to alkenes is controlled mainly by the steric effect of the substituent.
- Negoro, Takeshi,Ikeda, Yoshitsugu
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p. 2547 - 2552
(2007/10/02)
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- One-pot Conversions of Amines into Olefins via Non-isolated Pyridinium Intermediates
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Secondary alkyl primary amines are converted by the pyrylium salt (1) directly at 20 deg C into olefins via the corresponding secondary carbenium ions.Isomeric olefin mixtures are elucidated and result from carbenium ion rearrangements.
- Katritzky, Alan R.,Lloyd, Jeremy M.
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p. 2347 - 2352
(2007/10/02)
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- Palladium-Catalyzed Three Carbon Chain Extension Reactions with Acrolein Acetals. A Convenient Synthesis of Conjugated Dienals
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A variety of vinylic halides has been found to react with acrolein or methacrolein acetals and amines with palladium catalysts to form 5-amino 3-enal acetals and/or dienal acetals.The reaction products yield 2,4-dienals on treatment with aqueous acids, in moderate to good yields.Crotonaldehyde dimethyl acetal also undergoes the reaction, but only in low yields. 3-Buten-2-one ethylene ketal reacted well under the same conditions, however, and Hofmann elimination and hydrolysis of the product amine gave (E,E)-3,5-heptadien-2-one in 90percent yield.
- Patel, Babu A.,Kim, Jin-Il I.,Bender, Diana D.,Kao, Lien-Chung,Heck, Richard F.
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p. 1061 - 1067
(2007/10/02)
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