Strain-release electrophilic activation via E-cycloalkenones.
UVA irradiation (ca. 350 nm) of a mixture of cyclic enones and nitrogen heterocycles leads to efficient formation of the 1,4-adducts in a variety of solvents, at room temperature. These reactions likely proceed through strained E-cycloalkenone intermediates, as suggested by low-temperature generation/trapping experiments monitored by 1H NMR. These results demonstrate that E-cycloalkenones are good electrophiles despite their known tendency to favor a conformation in which the carbonyl is not fully conjugated with the double bond.
Moran
Joseph
J
Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, Canada, K1N 6N5.
Dornan
Peter
P
Beauchemin
André M
AM