Reductive bromination of aromatic aldehydes using alkylboron dibromides (original) (raw)

A green bromination method for the synthesis of benzylic dibromides

Tetrahedron Letters, 2014

Reported herein is the identification of a new methodology for the dibromination of benzylic diols. This method proceeds in moderate to good yields for a wide variety of electron-deficient, electron-neutral, and electron-rich aromatic substrates. Moreover, the reagent, 1,3-dibromo-5,5-dimethylhydantoin, and the solvent, tetrahydrofuran, are substantially more environmentally benign than traditional solvents and reagents used for bromination. The utility of this methodology was demonstrated in the high-yielding synthesis of a key intermediate in the synthesis of omeprazole

Rapid and Total Bromination of Aromatic Compounds Using TsNBr 2 Without Any Catalyst

Synthetic Communications, 2014

N,N-Dibromo-p-toluenesulfonamide (TsNBr 2 ) has been found to be a new reagent for bromination of aromatic compounds. The reaction is extremely fast and goes into completion instantaneously at ambient temperature to produce exclusively the corresponding polybrominated product. This procedure is applicable to various phenols, anisole, and anilines to give corresponding polybrominated compound as a single product in excellent yield.

A New Regioselective Bromination of Activated Aromatic Rings

Synthesis, 2006

An efficient and highly regioselective bromination of activated aromatic rings promoted by tribromoisocyanuric acid by in situ generation of Br + has been developed. A range of aromatic compounds were reacted with tribromoisocyanuric acid and trichloroisocyanuric acid and sodium bromide.

Regioselective and high-yielding bromination of aromatic compounds using hexamethylenetetramine–bromine

Tetrahedron Letters, 2005

A regioselective and highly efficient method for bromination of aromatic compounds in the presence of a stoichiometric amount of hexamethylenetetramine-bromine (HMTAB) as an efficient reagent in dichloromethane is reported. The selectivity depends on the temperature and nature of the substituent on the substrate. The reactivity of this reagent was increased by supporting it to silica gel for bromination of less activated compounds.

Radical mediated-direct conversion of aldehydes into acid bromides

Tetrahedron Letters, 2007

A method of preparing acid bromides directly from aldehydes with Br 3 CCO 2 Et under radical conditions was developed. Aromatic aldehydes with electron-donating group were found to be more reactive than aromatic aldehydes with electron-withdrawing group and aliphatic aldehydes under reaction conditions.

High temperature bromination VI: Bromination of benzobarrelene

Tetrahedron, 1994

Alslrrer: The electrophilic addition of bromine to benzobarrelene in chloroform at 10° C followed by mpeated chnnnatography combined with fractional crystallization allowed us to isoktte ten products 12-21 StnWual determination of these compounds revealed that the banelene skeleton was rearranged completely. 18-21 are alcohol compounds which arise from hydrolysis of 12, 13, 14, andl5, mspectively. High tempemture bmmination of benzobarrelene in decalin at I50 Oc followed by qxated chmm&gmphy combined with fractional crystallization gave us 18 products. Nonrevranged products 24,25, and 26 have been isolated in 50% yield. All compounds have been characterized properly, especially by 200 MHz lH NMR and 50 M?lz 13C NMR spectra. Furthermore, it has been concluded that hi8h tempetatme bMmi&at of bicyclic systems gives more non-nxmutged products. If the molecule ismaestrained,thetendencytoreanange~a9inthewseofbenz~~e.