Boron-Nitrogen Compounds. XIV. The Preparation of Vinyldibromoborane and Some of Its Reactions with Amines

Synthesis and Reactions of Borazines

“…The synthesis involves reaction of bis(dimethylamino)vinylborane (51) at 80-100 °C while bubbling with ammonia gas. 79 Similarly, the reaction of bis(dimethylamino)vinylborane (51) with ammonia at room temperature, followed by heating to 80-100 °C for 2 h, gave B-trivinylborazine (52) in 49% yield. 79 The bis(dimethylamino)vinylborane precursor (51, R = bis(dimethylamino)) can be easily prepared from the borylation of vinylmagnesium bromide in anhydrous ether or from bubbling of dimethylamine into vinyldibromo-borane solution.…”

“…79 Similarly, the reaction of bis(dimethylamino)vinylborane (51) with ammonia at room temperature, followed by heating to 80-100 °C for 2 h, gave B-trivinylborazine (52) in 49% yield. 79 The bis(dimethylamino)vinylborane precursor (51, R = bis(dimethylamino)) can be easily prepared from the borylation of vinylmagnesium bromide in anhydrous ether or from bubbling of dimethylamine into vinyldibromo-borane solution. 79,80 In 2000, Framery and Vaultier successfully improved the yield of B-trivinylborazine (52) to 64% by employing 1 mol% phenothiazene as an additive.…”

“…79 The bis(dimethylamino)vinylborane precursor (51, R = bis(dimethylamino)) can be easily prepared from the borylation of vinylmagnesium bromide in anhydrous ether or from bubbling of dimethylamine into vinyldibromo-borane solution. 79,80 In 2000, Framery and Vaultier successfully improved the yield of B-trivinylborazine (52) to 64% by employing 1 mol% phenothiazene as an additive. 43 The scope of this method also includes synthesis of B-triethynylborazine, B-trimethylborazine, B-tributylborazine, and Btriphenylborazine.…”

“…43 The scope of this method also includes synthesis of B-triethynylborazine, B-trimethylborazine, B-tributylborazine, and Btriphenylborazine. 43 Scheme 34 B-Trifunctionalized borazine from bis(dimethylamino)vinylborane by heating while bubbling the reaction with ammonia 79 Condensation of trialkylborane with alkyl-or arylamines leads to the corresponding B,N-functionalized borazines. 63 Wiberg and Hertwig observed the formation of Btrifluoroborazine (54) from the reaction of fluorodimethylborane ( 53) and methylamine at 400 °C (Scheme 35).…”

“…77 Scheme 33 B-Tris(ethylamino)borazine by condensation of tris(ethylamino)borane 77 Another synthetic approach involves reaction of trialkylborane with ammonia in an autoclave at 200-450 °C to afford B-trimethylborazine and B-triethylborazine. [78][79] Following this tactic, in 1964 Fritz and co-workers successfully prepared B-trivinylborazine (52) in 49% yield (Scheme 34). The synthesis involves reaction of bis(dimethylamino)vinylborane (51) at 80-100 °C while bubbling with ammonia gas.…”