Premium
Cycloaddition of dimethyl acetylenedicarboxylate to indoles. Isolation of a [2 + 2] adduct
Author(s) -
Augusto J.,
Rodriguez R.,
Verardo L. I.
Publication year - 1983
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570200523
Subject(s) - dimethyl acetylenedicarboxylate , chemistry , boron trifluoride , adduct , cycloaddition , solvent , medicinal chemistry , organic chemistry , catalysis , cyclobutene , ring (chemistry)
Thermal reaction of 1,2,3‐trimethylindole (1) and 1,3‐dimethylindole (5) with dimethyl acetylenedicarboxylate in the presence of boron trifluoride etherate gave cyclobutene derivatives 2 and 7 that were isolated for the first time in good yields under themal conditions. In a polar solvent and with an excess of catalyst, 4‐methoxy‐2,4a‐dihydro‐4a,9‐dimethyl‐2‐oxacarbazole 4 was obtained in yields up to 72%.