... Please enable JavaScript to use all the features on this page. Tetrahedron Letters. Volume 26, Issue 25, 1985, Pages 2969–2972. Cover image Cover image. ... March 1985, Available online 9 March 2001. Abstract. Cycloaddition reaction of a pyrrole-carbene chromium complex with alkyne in the presence of acetic anhydride and triethylamine provided the acetylated hydroindoloquinone derivative. References. ... 2; A. Yamashita, TA Scahill; Tet. Lett., 23 (1982), ...