583. Preparation, stability, and complex formation of aryloxyboron compounds

Abstract

A number of triaryl borates have been prepared by interaction of boron trichloride and the phenol or naphthol, and steric and polar factors concerning their amine addition compounds are discussed. Ammonia forms 3 : 1 and 2 : 1 complexes respectively with tris-2 : 4 : 6-trichlorophenyl and triphenyl borate. Whereas P-nitrophenyl, o-tolyl, and o-chlorophenyl dichloroboronite are unstable, o-nitrophenyl dichloroboronite is by cornparison remarkably stable, a property ascribed to internal co-ordination ; but all form stable pyridine complexes. There is evidence of isolation of the mixed borate, ethyl di-o-nitrophenyl borate, which with pyridine gives triethyl borate, and the pyridine complex of the triaryl borate.TRIARYL BORATES have previously been obtained by heating a mixture of a phenol and boron trichloride (in a sealed tube),l boric acid,293 boric oxide,* or boron acetate.sv6 A number of triaryl borates (Table 1) have now been prepared by the addition of a solution of the phenol (3 mols.) in methylene dichloride to boron trichloride (1 mol.) at -70". Advantages of this procedure are that nearly quantitative yields are obtained, the only other product is gaseous hydrogen chloride, which together with the low-boiling solvent can readily be removed, the reaction is quick and easily controlled at low temperatures, and functional groups may be present.

Umlagerung von Allyl‐aryläthern und Allyl‐cyclohexadienonen mittels Bortrichlorid

“…Der gebildete Dichlorborsaure-arylester konnte selbst noch als Lewissaure (vgl. [42]) die Umlagerung von Allyl-phenylather einleiten. Auf der anderen Seite ist bekannt , dass vergleichbare Dichlorborsaureester leicht in Chlorborsaurediarylester und Bortrichlorid disproportionieren konnen [42].…”

“…[42]) die Umlagerung von Allyl-phenylather einleiten. Auf der anderen Seite ist bekannt , dass vergleichbare Dichlorborsaureester leicht in Chlorborsaurediarylester und Bortrichlorid disproportionieren konnen [42]. Eine Zuni Schluss sei noch auf den speziellen ccfJara-Effekt H eingegangen, der bei cler Umlagerung von a-Methylallyl-arylathern mit o-standiger Alkylgruppe in Gegenwart von Bortrichlorid beobachtet wird (vgl.…”

Reactions Of Boron Trichloride With Organic Compounds

“…(10 hr.) (34). The 2,4,6-trichlorophenyl and p-nitrophenyl compounds were, however, stable under similar conditions.…”

“…; no yields were given and chlorinated by-products were claimed (123). More recently it ivas found that phenols react (equation 23) rapidly, exothermally, and nearly quantitatively with boron trichloride to produce stepwise dechlorination of the trichloride, and that the nature of the product depended upon the proportions in wrhich the reagents were mixed (33,34). In this respect there is marked resemblance between the phenols and alcohols, and differences in the two systems arise mainly out of the different behavior of the aryloxyboron chlorides and triaryl borates compared with their aliphatic analogs.…”

Redistribution and Exchange Reactions in Groups IIB-VIIB

“…(130) at room temperature. Attempts to isolate mixed esters of boron have failed except for cyclic compounds (65) and certain o-nitrophenoxy esters (35) which have some feature stabilizing the mixed compound.…”