Tributyl borate

Various borate esters are chemostetilants for house flies (51). Tributyl borate, available from Eagle-Picher, Miami, Oklahoma, which is isotopically enriched in boron-10, is being used as a chemical precursor in the synthesis of pharmacologically active boron compounds suitable for boron neutron capture therapy. 

Tribromopropane Tributylamine Tributyl borate Tributyl phosphate Tributyl phosphite Trichloroacetaldehyde... 

The reaction of 4-lithiodibenzofuran with 0-methylhydroxylamine provides a synthesis of the 4-amino compound, and reaction with iodine leads to the iodo compound. The reactions of 4-lithiodibenzofuran with tributyl borate,diphenyl disulfide, A,A/-dimethylcarbamoyl chloride, and cyanuric chloride have been studied. 

Metalated ferrocenes have served as valuable intermediates for the synthesis of a number of other derivatives. Treatment of lithiated ferrocenes with tributyl borate followed by hydrolysis leads to ferroceneboronic acid (XXXIII) as well as the diboronic acid (73). Ferroceneboronic acid, like benzeneboronic acid, is readily cleaved by cupric bromide or cupric chloride to form the corresponding halo derivatives (XXXIV). Ferrocene-l,l -diboronic acid reacts in the same manner, and either one or two carbon-boron bonds can be cleaved. Further reactions of this type have led to a variety of mixed dihaloferrocenes (73, 75). 

Sodium triacetoxyborohydride, 283 Tetrabutylammonium iodide-Boron trifluoride etherate, 287 Tributylborane, 325 Tributyl borate, 326 Triethylborane, 33, 292 Trimethyl borate, 218 Zinc borohydride, 167 Chromium Compounds Arene(tricarbonyl)chromium complexes, 19... 

SYNTHESIS A solution of 15 g 1,3-diethoxybenzene and 15 mL of N,N,N ,N -tetramethylethylenediamine in 200 mL anhydrous Et20 was placed in a He atmosphere, magnetically stirred, and cooled to 0 °C with an ice bath. Over the course of 10 min there was added 63 mL of a 1.6 M solution of butyllithium in hexane, which produced a fine white precipitate. After an additional 15 min stirring, 20 mL of tributyl borate was added which dissolved the precipitate. The stirring was... 

Aryl halides of many different types, including simple unsubstituted halides, may be conveniently converted into phenols by an indirect route involving the preparation of an arylboronic acid and its subsequent oxidation with hydrogen peroxide. The arylboronic acid (3) is normally prepared by reaction of the corresponding arylmagnesium halide with a borate ester (typically tributyl borate) at between —60 and — 80 °C, to yield the dialkyl boronate ester (2) which is then hydrolysed to the arylboronic acid (3). The latter may be isolated, purified and then oxidised with hydrogen peroxide as described in the preparation of m-cresol (Expt 6.101). Alternatively the crude reaction mixture from the preparation of (3) may be treated directly with hydrogen peroxide.36... 

Notes. (1) The tributyl borate is available commercially (Aldrich) and packaged in Sure/Seal bottles under nitrogen. 

A new method for the ortho hydroxylation of aromatic aldehydes via orrho-lithiated arcnnatic aminoal-koxides has recently been reported by Einhom et al Fonnation of the aminoalkoxide serves two purposes. Firstly, the aldehyde group is protected and, secondly, the aminoalkoxide directs lithiation to the ortho position. Oxidation of the lithio species was effected by either MoOPH or molecular oxygen, albeit in poor yield. Alternatively, a two-step, one-pot condensation of the lithio intermediate with tributyl borate followed by oxidation with hydrogen peroxide gave the ortho-hydroxy aldehydes (24) in slightly better yields (Scheme 9). 

SYNS BORESTER2 BORIC ACID, TRI-sec-BUTYL ESTER BUTYL BORATE n-BUTYL BORATE TRIBUTOXYBORANE TRI-n-BUTOXYBORANE TRIBUTYL BORATE... 

C10H3003SI4 decamethyltetrasi I oxane 141-62-8 liquid 1.220 1 25327 C12H27B03 tributyl borate 688-74-4 in benzene 0.779 1... 

Another example for the C5 + C strategy is the method published by Anieta et al. (116) in which the enedione 153 was reacted with aromatic aldehydes. The yield of this condensation could be improved by Mann et al. (117) using the magnesium enolate of the enedione 153 in the presence of tributyl borate and butylamine (117). 

Tricrotylborane, in 75% yield, and tri(2-methylallyl)borane have been synthesized by the above procedure. Tributyl borate can be also used for these preparations in place of boron trifluoride etherate. 

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