Nitrile Ylides: Allenic and Propargylic Structures from Pyrazinylnitrenes. Experimental and Theoretical Characterization.

Didier Bégué (1) , Chris Addicott , Riko Burgard , Pawel Bednarek , Emilie Guille , Isabelle Baraille (1) , Curt. Wentrup

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

Matrix photolysis of 2-pyrazinyl azides/tetrazolo[1,5-a]pyrazines generates nitrile ylides 15 via pyrazinylnitrenes 13 and triazacycloheptatetraenes 14. The nitrile ylides 15 are characterized by IR spectroscopy in conjunction with harmonic and anharmonic vibrational frequency calcns. The nitrile ylides exist in the matrixes in the Z,Z-conformations in which they are born. Substitution on the nitrile carbon of nitrile ylides has a profound effect on their structure. Even different conformers of the same mol. can have differences up to 200 cm-1 in the IR absorptions of the ylide moieties. Nitrile ylides 15a and 15b (R = H or Cl, R' = H) have allenic structures (15Allenic). Nitrile ylide 15c (R = R' = CH3) has a distinctly propargylic structure (15Propargylic) in the exptl. obsd. Z,Z-conformation. [on SciFinder(R)]

Mots clés: nitrile ylide allenic propargylic structure photolysis IR

Domaines: Chimie théorique et/ou physique

Didier Bégué, Chris Addicott, Riko Burgard, Pawel Bednarek, Emilie Guille, et al.. Nitrile Ylides: Allenic and Propargylic Structures from Pyrazinylnitrenes. Experimental and Theoretical Characterization.. Journal of Organic Chemistry, 2014, 79 (Copyright (C) 2017 American Chemical Society (ACS). All Rights Reserved.), pp.2148--2155. ⟨10.1021/jo500002r⟩. ⟨hal-01536060⟩