A MULTINUCLEAR NMR-STUDY OF THE CYCLOADDITION REACTION OF SNSASF6 WITH TERT-BUTYLPHOSPHAACETYLINE (CH3)(3)CCP LEADING TO THE 5-TERT-BUTYL-1,3,2,4-DITHIAZAPHOSPHOLIUM (CH3)(3)CCPSNS- A PRELIMINARY ACCOUNT OF THE NOVEL EXCHANGE OF A CYCLIC PHOSPHORUS BY NITROGEN IN THE REACTION OF(CH3)(3)CCPSNS+ WITH ASIDE N-3(-) LEADING TO 5-TERT-BUTYL-1,3,2,4-DITHIAZIAZOLYL (CH3)(3)CCNSNS( CATION )

The cycloaddition reaction of SNS+ (as the AsF6- salt) with 5-tert-but ylphosphaacetyline (CH3)(3)CCP in sulfur dioxide solution at -60 degre es C gave (CH3)(3)CCPSNS+, the first identified example of a 1,3,2,4-d ithiaza-phospholium heterocycle RCPSNS(+). The cycloadduct was charact erized by multinuclear NMR (H-1, C-13, N-14, N-15, P-31) spectroscopy at low temperature. Reduction of 6 pi (CH3)(3)CCPSNS+ in situ with SbP h(3) in the presence of Me(4)NCl led to a radical, which may be the 7 pi tert-butyl-1,3,2,4-dithiazaphospholyl (CH3)(3)CCPSNS+. The reaction of 5-tert-butyl-1,3,2,4-dithiazaphospholium (CH3)(3)CCPSNS+ with azid e N-3(-) surprisingly gave the previously known 5-tert-butyl-1,3,2.4-d ithiadiazolyl (CH3)(3)CCNSNS. The conversion of (CH3)(3)CCPSNS+ to (CH 3)(3)CCNSNS by the net replacement of a cyclic phosphorus with nitroge n is unprecedented.