tris(2-perfluorohexylethyl) tin azide:: A new reagent for preparation of 5-substituted tetrazoles from nitriles with purification by fluorous organic liquid-liquid extraction

The synthesis of a new fluorous tin azide, (C6F13CH2CH2)(3)SnN3, is reported and this reagent is used to make tetrazoles in both traditional and phase-switching modes. In the traditional mode, the tin azide is reacted with nitriles followed by HCl cleavage to provide the tetrazoles and the fluorous tin chloride (which can be reconverted into the tin azide). In the switching mode, the initial tin tetrazole is purified by fluorous/organic liquid-liquid extraction prior to destannylation. This provides pure products even in incomplete reactions or with impure starting materials, but it only works for smaller nitriles. (C) 1999 Elsevier Science Ltd. All rights reserved.