Proximity-Assisted Cycloaddition ReactionsFacile Lewis Acid-Mediated Synthesis of Diversely Functionalized Bicyclic Tetrazoles
作者:Stephen Hanessian、Daniel Simard、Benoît Deschênes-Simard、Caroline Chenel、Edgar Haak
DOI:10.1021/ol703071c
日期:2008.4.1
Aliphatic azidonitriles separated by three or four carbon atoms undergo facile Lewis acid-induced cycloadditions to give bicyclic tetrazoles, even at 0 degrees C. Extension to 3-azido-2-aryl-1,3-dioxolanes and the corresponding 1,3-dioxanes in the presence of TMSCN and BF3 center dot OEt2 leads to a series of diversely functionalized novel oxabicyclic tetrazoles. The reactions represent new aspects of proximity-assisted dipolar cycloadditions that afford thermodynamically controlled enantiopure products proceeding through discrete oxocarbenium ion intermediates.