... Tetrahedron. Volume 60, Issue 7, 9 February 2004, Pages 1505–1511. Cover image Cover image. ... The pyrrolyl α-diazo-β-ketoesters 6 and 7 were generated (ca. 65%) by a diazo transfer reaction on the β-ketoesterers 4 and 5 with p-toluenesulfonylazide. ...