5‐Lithio‐2H‐tetrazolium‐Carbenoide: NMR‐spektroskopischer Nachweis und Reaktionen mit Stickstoffelektrophilen

Abstract

Zr-Me). Die Anionen in 1 und 3 zeigen jeweils ihnliche Resonanzsignale wie die in 2 bzw. 4.

Organometallic Tetrazole Derivatives: Preparation and Application to Organic Synthesis

“…This fragmantaion path was recently confirmed by obtaining N,N-disubstituted cyanamide 19 at successive treatment of 1-benzyloxymethyltetrazole with butyllithium and benzyl bromide at -78°C in THF in the presence of N,N-dimethyltetrahydropyrimidin-2-one [24]. 5-Lithio-2,3-diaryltetrazolium salts 6 obtained at -78°C at warming to room temperature suffered the opening of the tetrazole ring to furnish 2,3-diaryl-1-cyanoazimines in 63-85% yields [26,27].…”

“…The treatment of tetrazolium salt 6 with diazonium salts and tosyl azide resulted in formation of 5-arylazo and 5-azido-2,3-diaryltetrazolium salts respectively [27].…”

“…The process is commonly carried out in THF, more seldom in ethyl ethter, and sometimes in the presence of N,N,N',N'-tetramethylethylenediamine (TMEDA). In this way series of 5-lithio-1 -R -t e t r a z o l e s 4 ( R = M e [ 1 0 ] , B z [ 2 0 , 2 1 ] , 4-MeOC 6 H 4 CH 2 [21], BzOCH 2 [22]), 5-lithio-2-Rtetrazoles 5 (R = Me 3 SiCH 2 CH 2 OCH 2 [23], BzOCH 2 [24], azabicycloalkyl [25]), and 5-lithio-2,3-diaryltetrazolium salts 6 [26,27] were prepared. In view of the high reactivity these compounds were not isolated as individual substances but were applied to further reactions in solution.…”

1,3- and 1,4-Substituted tetrazolium salts

“…It was shown, in particular, that the substitution of lithium for hydrogen in 2,3-diaryltetrazolium salts occurs under the action of tert-butyllithium or lithium bis(trimethylsilyl)amide. 90,91 The condensation of 1,3-diphenyltetrazolium tetrafluoroborate with a diazonium salt in the presence of 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU), which favours the formation of a mesoionic carbene, viz., 1,3-diphenyltetrazolylene (54), has been described. 60 ClO À 4-Me2NC6H4N N BF À It was found that 1,3-diaryltetrazolium salts undergo mercuration upon heating with mercury(II) acetate in dimethyl sulfoxide to yield bis(tetrazolio)mercury(II) salts 55 the mercury atom in which is easily replaced by a halogen.…”

“…It was shown, in particular, that the substitution of lithium for hydrogen in 2,3-diaryltetrazolium salts occurs under the action of tert-butyllithium or lithium bis(trimethylsilyl)amide. 90,91 The condensation of 1,3-diphenyltetrazolium tetrafluoroborate with a diazonium salt in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), which favours the formation of a mesoionic carbene, viz., 1,3-diphenyltetrazolylene (54), has been described. 60 ClO À…”