文摘
2-(Dimethylamino)pyridine (2-DMAP) and 2-(dimethylamino)pyrimidine derivatives form 畏2-bound complexes with the dearomatization agent {TpW(NO)(PMe3)} that are each capable of undergoing a double protonation. In the case of 2-DMAP, the resulting 蟺-allyl species reacts with the 伪-carbon of thiophene or 2-methylfuran, thereby coupling the heterocyclic rings. In the case of the thiophene-derived product, subsequent oxidative decomplexation using ceric ammonium nitrate affords a novel organic amidine derivative. Examples of tungsten-promoted acetylation and fluorination of the aminopyridine ring are also described.