Intermolecular hydroaminations via strained (E)-cycloalkenes.
A photoinduced procedure for the intermolecular hydroamination of alkenes using azoles is described. This reaction occurs in modest to good yield for 6- and 7-membered cyclic alkenes. Upon irradiation at 254 nm in the presence of methyl benzoate and a small amount of triflic acid as an additive (20 mol %), imidazoles, pyrazoles, triazoles, and tetrazole can react with the alkene to afford complex Markovnikov adducts. The proposed mechanism involves photoisomerization to generate highly strained (E)-cycloalkene intermediates and (E)-cycloalkene protonation followed by reaction with the azole nucleophile. Alkene isomerization was found to be a competing side reaction under these conditions.
Moran
Joseph
J
Department of Chemistry, Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, Canada K1N 6N5.
Cebrowski
Pamela H
PH
Beauchemin
André M
AM
D000586:Amination; D001393:Azoles / Q000737:chemistry; D001565:Benzoates / Q000737:chemistry; D003516:Cycloparaffins / Q000138:chemical synthesis / Q000737:chemistry*; D006865:Hydrogenation; D007097:Imines / Q000737:chemistry; D015394:Molecular Structure; D010777:Photochemistry
D001393:Azoles; D001565:Benzoates; D003516:Cycloparaffins; D007097:Imines; C044605:methyl benzoate