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

详细信息    查看全文

• 作者：Didier B茅gu茅 ; Chris Addicott ; Riko Burgard ; Pawel Bednarek ; Emilie Guille ; Isabelle Baraille ; Curt Wentrup
• 刊名：Journal of Organic Chemistry
• 出版年：2014
• 出版时间：March 7, 2014
• 年：2014
• 卷：79
• 期：5
• 页码：2148-2155
• 全文大小：422K
• 年卷期：v.79,no.5(March 7, 2014)
• ISSN：1520-6904

文摘

Matrix photolysis of 2-pyrazinyl azides/tetrazolo[1,5-a]pyrazines generates nitrile ylides <b>15b> via pyrazinylnitrenes <b>13b> and triazacycloheptatetraenes <b>14b>. The nitrile ylides <b>15b> are characterized by IR spectroscopy in conjunction with harmonic and anharmonic vibrational frequency calculations. The nitrile ylides exist in the matrices 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 molecule can have differences up to 200 cm^鈥? in the IR absorptions of the ylide moieties. Nitrile ylides <b>15ab> and <b>15bb> (R = H or Cl, R鈥?= H) have allenic structures (<b>15b> <b>Allenicb>). Nitrile ylide <b>15cb> (R = R鈥?= CHb>3b>) has a distinctly propargylic structure (<b>15b> <b>Propargylicb>) in the experimentally observed Z,Z-conformation.