Expedient one-step synthesis of nitrogen stilbene analogs by transition metal-free hydroamination of arylacetylenes with pyrroles
摘要:
A novel family of nitrogen stilbene analogs, 1-styrylpyrroles, has been synthesized in good to excellent yields by a straightforward facile transition metal-free addition of pyrroles to arylacetylenes in the KOH/DMSO system (90-120 degrees C, 5-13 h). Thermodynamically controlled E/Z-isomer ratio of 1-styrylpyrroles depends on structure of both pyrroles and acetylenes ranging from ca. 100% E-stereoselectivity (for the pair unsubstituted pyrrole phenylacetylene) to 90, 96% Z-stereoselectivity (for the pairs: 2-phenylpyrrole-phenylacetylene and 2-(2-thienyl)pyrrole-phenylacetylene, respectively). (C) 2011 Elsevier Ltd. All rights reserved.