1,3-Dipolar cycloadditions of 9-diazofluorenes and diphenyldiazomethane to 2-acyl-2H-1,2,3-diazaphospholes

✍ Scribed by Xiangyun Guo; Li Feng; Quanrui Wang; Zhiming Li; Fenggang Tao

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2006
• Tongue: English
• Weight: 483 KB
• Volume: 43
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570430215

✦ Synopsis

2H-1,2,3-diazaphospholes 3 underwent ready 1,3-dipolar cycloaddition reactions with 9-diazofluorenes as the 1,3-dipole, yielding the respective bicyclic phosphiranes 5 or trimers 7 depending on the reaction conditions employed. The reaction is believed to proceed via the formation of the [3+2]cycloaddition adducts followed by elimination of nitrogen from the cyclic azo moiety. In the case of 3c, the phosphatetraazabicyclooctadiene compound 6 has been isolated with no loss of nitrogen. Likewise, the dipolar cycloaddition reaction of diphenyldiazomethane with the >C=P-moiety as the 1,3-dipolarophile gave phosphadiazabicyclohexenes 8 in 32-68% yields.