Diels-Alder cycloadditions of 3,5-dibromo-2-pyrone: a new ambident diene.
D-A cycloadditions of 3,5-dibromo-2-pyrone were investigated with a series of electronically and sterically distinct dienophiles. Our results showed that it is a highly potent ambident diene, being more reactive and stereoselective than monobromo-2-pyrones, and thus capable of generating a variety of bicycloadducts in much higher chemical yields and endo/exo ratios than monobromo-2-pyrones. Another interesting feature of this study is that the two bromine groups on the cycloadducts could be independently manipulated to produce other synthetically useful bicyclolactones.
Cho
Cheon-Gyu
CG
Department of Chemistry, Hanyang University, Seoul 131-791, Korea. ccho@hanyang.ac.kr
Kim
Yong-Woo
YW
Lim
Young-Kwan
YK
Park
Jung-Sang
JS
Lee
Haiwon
H
Koo
Sangman
S
D000466:Alkadienes / Q000138:chemical synthesis* / Q000737:chemistry; D002762:Cholecalciferol / Q000031:analogs & derivatives; D018360:Crystallography, X-Ray; D003500:Cyclization; D011753:Pyrones / Q000737:chemistry
C450850:3,5-dibromo-2-pyrone; D000466:Alkadienes; D011753:Pyrones; D002762:Cholecalciferol