Competitive thermal ene reaction and Diels–Alder reactions of 2-[N-(alk-2-enyl)benzylamino]-3-vinylpyrido[1,2-a]pyrimidin-4(4H)-ones
作者:Michihiko Noguchi、Toshiya Sunagawa、Ryosuke Akao、Hisashi Yamada、Hidetoshi Yamamoto、Akikazu Kakehi
DOI:10.1016/j.tet.2007.03.037
日期:2007.5
Thermal reaction of 2-[N-(alk-2-enyl)benzylamino]-3-(2-substituted and 2,2-disubstituted)vinylpyrido[1,2-a]pyrimidin-4(4H)-ones gave azepine, the desired ene products, and/or pyran derivatives. The formation of the latter was responsible for the [4+2] cycloaddition reaction between the α,β-unsaturated ester carbonyl moiety as a diene part and the alkenylamino moiety as an ene one. The reaction features
2- [ N-(烷-2-烯基)苄氨基] -3-(2-取代和2,2-二取代)乙烯基吡啶并[1,2 - a ]嘧啶-4(4 H)-的热反应得到氮杂gave ,所需的烯产物和/或吡喃衍生物。后者的形成负责作为二烯部分的α,β-不饱和酯羰基部分与作为烯基的烯基氨基部分之间的[4 + 2]环加成反应。反应特征取决于乙烯基和链烯基对应物上的取代基的种类。乙烯基部分上的强吸电子取代基或烯基上的供电子取代基将反应特征从烯反应转变为杂狄尔斯-阿尔德反应。