Boron trichloride, with alcohols

Ebelman, J.J. and Bouquet, M. (1846) Ann. Chem. Phys. 17, 54. Ebelman was the first person to describe alkoxide synthesis. This paper reported the synthesis of boron methoxide, ethoxide, and pentoxide by the reaction of boron trichloride with the appropriate alcohol. These alkoxides can be used in the synthesis of borosilicate glasses. 

Enal (54) undergoes intramolecular carbonyl-ene cyclization to give cis- and trans-alcohols (55). Lewis acids such as boron trichloride and tin tetrachloride (and also dimethylaluminium chloride ) give predominantly the cis product, while the preference is reversed with the bulky MeALAr2(Ar = OC6H2 -Br-2, 6-di-Bu ). Open and closed chair-like transition states are considered and compared with previous... 

Boron trichloride and tribromide successfully polymerize styrenes and isobutene. These Lewis acids are typically used in combination with water or alkyl chlorides, acetates, ethers, and alcohols [105,153]. In contrast to earlier reports, BC13 can self-initiate polymerization of styrene and isobutene [137] by haloboration, and subsequent activation of the resulting alkyl chlorides by excess Lewis acid. Direct initiation was confirmed by the formation of lower molecular weight polymers than pre-... 

The alkoxydi(sulfonyl)methane shown in Scheme 128 (entry b) has been used as a useful carbonyl 1,1-dipole synthon ( C°-0). Its alkylation with alkyl halides is best achieved using CS2CO3 in DMF at 50 °C, and its palladium-catalyzed allylation requires the use of phase-transfer conditions (Scheme 128, entry b). The unmasking of the carbonyl group was then achieved by reacting the resulting disulfone with boron trichloride (-78 C, CH2CI2) followed by the addition of alcohols or amines to provide esters or amides respectively (Scheme 128, entry b). ... 

Boron trichloride reacts with an acetal, or with a mixture of an aldehyde and an alcohol, to give a 1-chloroalkyl ether (yields 40-85%). The l-chloroalkyl ethers are of interest because they are dehydrochlorinated by trimethylamine to give vinyl ethers. 

TETROXIDO de NITOGENO (Spanish) (10544-72-6) Noncombustible, but supports combustion of combustible materials. A powerful oxidizer. Water contact produces nitric acid and nitric oxide. Incompatible with nitric oxide reacts with air, producing additional nitrogen tetroxide. Violent reaction with strong reducing agents, anhydrous ammonia, alcohols, barium oxide, boron trichloride, carbon disulfide, chlorinated hydrocarbons, cyclohexane, difluoro-trifluoromethylphosphine, dimethyl sulfoxide, formaldehyde, ethers, fluorine, formaldehyde, halocarbons, hydrocarbons, metal acetylides, metal carbides, metal powders, metal carbonyls. 

It is of interest to note in passing that In more recent work (ref.72), use has been made in synthesis of the transformation of chalcones to isoflavones with thallium(lll) nitrate. Thus, 6-acetyl-2,2-dimethyl-7-hydroxy-5-methoxychromanone was converted to the chalcone with 2,4-dibenzyloxybenzaldehyde. The O-acetyl derivative by treatment with the thallium reagent followed by acidic cyclisation gave a bischromanone structure. Selective reduction of the least hindered carbonyl group in the bischromanone, acidic dehydration of the resultant alcohol and final debenzylation with boron trichloride gave the linear isofiavone. 

Some cyclodiphosphazanes can be dehydrohalogenated to yield cyclo tri, or higher cyclophosp-hazenes (7.260), while others react with boron trichloride to give a cyclic zwitterion (7.261). Alcohols or alkoxides will produce monophosphazenes (7.262). 

Ethers can be cleaved rapidly at room temperature by diborane and halogen 0-Demethylation with retention of O-tosyl groups can be achieved with boron trichloride Alcohols can be obtained by degradation of carboxylic acids through carboxy-inversion of acyl peroxides . Aldehydes can be efficiently decarbonylated under mild conditions in the presence of a rhodium complex . A new mild and potentially selective method for the prepn. of aliphatic... 

Arylboronic and arylborinic acids have been produced from the hydrolysis of intermediates in the reactions of aryl-tin and aryl-lead compounds with diborane. The preparation of di[bis(trimethylsilyl)methyl]chloroborane from the reaction of bis(trimethylsilyl)methyl-lithium and boron trichloride has been published. A new reagent for O-ethylboranediylation, ethylbis-(2-isopropyl-6-methyl-4-pyrimidinyloxy)borane (3) has been synthesized and used to prepare O-ethyl-boranediyl derivatives of alcohols, phenols, alkanediols, D-mannitol, and l-arabinose. Borane-methyl sulphide reportedly reacts smoothly with primary, secondary, and tertiary alcohols and phenols to provide a general and convenient synthesis of borate esters. ... 

---