Alkynes nitrogen dioxide

The reactivity of alkanes and cycloalkanes are very low. Alkenes and alkynes containing double and triple bonds are reactive. The addition reactions follow Markovnikov rule. Conjugated dienes undergo Diels-Alder reactions. The substances that may react violently with unsaturated hydrocarbons are halogens, strong oxidizers, and nitrogen dioxide. Alkynes may form acetylides with certain metals. 

The photoelimination of carbon dioxide from esters and lactones is a process that has been the subject of detailed investigations. Discussion here is limited to nitrogen containing systems. 3,4-Diphenylsydnone (464), on irradiation in benzene, is converted via the nitrile imine 465 into 2,4,5-triphenyl-1,2,3-triazole (466)388 initial bond formation between N-2 and C-4 followed by loss of carbon dioxide to give the diazirine 467 is proposed to account for the formation of the nitrile imine. Nitrile imines generated in this way have been trapped with alkenes and alkynes to give pyrazoles389... 

The inverse electron-demand cycloaddition of electron-rich or strained alkynes with l,3,4-oxadiazin-6-ones leads to 2-pyrones because the adducts lose nitrogen (rather than carbon dioxide).. The example below shows the use of ethynyltribu-tyltin giving a mixture of regioisomers the stannylated pyrones can be utilised in the usual ways, for example for the introduction of halogen. ... 

---