Synthesis and Characterization of New Boron Compounds Using Reaction of Diazonium Tetraphenylborate with Enaminoamides.

A family of oxazaborines, diazaborinones, triazaborines, and triazaborinones was prepared by reaction of polarized ethylenes, such as β-enaminoamides, with 4-methylbenzenediazonium tetraphenylborates. The reaction conditions (stirring in CH 2 Cl 2 at room temperature (Method A) or stirring with CH 3 COONa in CH 2 Cl 2 at room temperature (Method B) or refluxing in the CH 2 Cl 2 /toluene mixture (Method C)) controlled the formation and relative content of these compounds in the reaction mixtures from one to three products. Substituted oxazaborines gradually rearranged into diazaborinones at 250 °C. The prepared compounds were characterized by 1 H NMR, 13 C NMR, IR, and UV-Vis spectroscopy, HRMS, or microanalysis. The structure of individual compounds was confirmed by 11 B NMR, 15 N NMR, 1D NOESY, and X-ray analysis. The mechanism of reaction of enaminoamides with 4-methylbenzenediazonium tetraphenylborate was proposed.