Solvent‐Free Synthesis of the Smallest Rotaxane Prepared to Date

Abstract

Small is beautiful: The [2]pseudorotaxane formed from dipropargylammonium tetrafluoroborate and the crown ether [21]crown-7 on SiO2 was stoppered with 1,2,4,5-tetrazine in a ball-milling process (see X-ray structure). This new and efficient solvent-free reaction led to the isolation in high yield (81 %) of the smallest [2]rotaxane reported to date. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2008/z803056_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.