Tris(biphenylenevinyl)methane

✍ Scribed by Prof. Dr. Richard Kuhn; Dr. Herbert Fischer

• Book ID: 101550389
• Publisher: John Wiley and Sons
• Year: 1964
• Tongue: English
• Weight: 132 KB
• Volume: 3
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.196401371

✦ Synopsis

is simply treated with the alkyne in acetic anhydride. Thus, dimethyl 5-methyl-l,2-trimethylenepyrrole-3,4-dicarboxylate is obtained in 76 % yield by merely warming proline with dimethyl acetylenedicarboxylate in acetic anhydride at 130 "C for 1 hr.

The kinetics of the release of carbon dioxide indicate that the acetylenic dipolarophile first combines with (31, presumably to form the bicyclic adduct (4) ; the elimination of CO:! from ( 4) is a rapid subsequent reaction. Compound (3) belongs to the azomethine-ylide class of 1,3-dipoles [4], cf. the sextet structure (20); here the 1,3-dipole system is part of an aromatic ring. H: Staudinger [5] has proposed the term "nitrenes" for azomethine ylides. The first representatives have recently been described [6].