Straightforward access to oxazaborines, diazaborinones and triazaborines by reactions of β-enaminoamides with 4-methylbenzenediazonium tetraphenylborate
                                
                                    
                                        作者:Markéta Svobodová、Jan Bárta、Petr Šimůnek、Valerio Bertolasi、Vladimír Macháček                                    
                                    
                                        DOI:10.1016/j.jorganchem.2008.10.004
                                    
                                    
                                        日期:2009.1
                                    
                                    The reaction of substituted beta-enaminoamides with 4-methylbenzenediazonium tetraphenylborate in dichloromethane produces besides the primary products of azo coupling reaction at the alpha-carbon atom of beta-enaminoamides, also mixtures of heterocyclic compounds of boron: 1,3,2 lambda(4)-oxazaborines, 1H-1,3,2 lambda(4)-diazaborine-4-ones and 4H-1,2,4,3 lambda(4)-triazaborines. Proportions of the products change depending on the reaction conditions, particularly depending on the presence or absence of base (sodium acetate) in the reaction mixture. The heterocyclic compounds were separated chromatographically and identified by means of X-ray, H-1, B-11, C-13 and N-15 NMR spectra and elemental analyses. (C) 2008 Elsevier B.V. All rights reserved.