Chemical transformation of tetraacetal tetraoxa-cages to aza-cages and amido-cages mediated by iodotrimethylsilane and the combination of chlorotrimethylsilane and sodium iodide in nitriles

Abstract

An one-pot conversion of tetraacetal tetraoxa-cages la-e to aza-cages 2a-e mediated by iodotrimethylsilane in alkyl nitriles at 25 degrees C via the ring expansion compound 9 as the reaction intermediate was discovered. A Ritter-type reaction was proposed for the mechanism of this conversion. On the other hand, reaction of tetraacetal tetraoxa-cages 1 with Me3SiCl and NaI in nitriles at 25 degrees C gave the amido-cages 12. Conjugated nitriles and Lewis acids, such as TiCl4 or BF3 . OEt2 were found to be ineffective for the conversion of era-cages to aza-cages. The structures of 2a and chemical transformation product 16 were proven by X-ray analysis. (C) 1998 Elsevier Science Ltd. All rights reserved.