Regiochemical aspects associated with the cycloaddition of diazopyrazolinones to electron deficient acetylenes

✍ Scribed by Anthony D. Woolhouse; Thomas C. Caruso; Albert Padwa

• Book ID: 104220789
• Publisher: Elsevier Science
• Year: 1982
• Tongue: French
• Weight: 193 KB
• Volume: 23
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)87290-1

✦ Synopsis

The regiospeclflclty with which members of the 4-dlazopyrazolln-5-one system undergo intermolecular cycloaddltlon to proplolate ester has been found to be markedly dependent upon the substltuent groups present. cr-Diazoketones represent an interesting class of compounds since several discrete modes of intermolecular cycloaddltlon are possible.' Amongst these are those involving reaction as a 1,3-dipole, either through the dlazoalkane moiety or through a reactive intermediate possessing the stoichiometry of a ketocarbene species derived from an initial loss of nitrogen. Much less common modes of addltlon involving the extended