Michael addition of chiral formaldehyde N,N-dialkylhydrazones to activated cyclic alkenes
作者:Juan Vázquez、Elena Cristea、Elena Díez、José M. Lassaletta、Auxiliadora Prieto、Rosario Fernández
DOI:10.1016/j.tet.2005.02.007
日期:2005.4
The nucleophilic conjugate addition of chiral formaldehyde N,N-dialkylhydrazones 1 to doubly activated cyclic alkenes 2–8 proceeds smoothly to afford the corresponding Michael adducts 14, 16, 18, 20, 22, 24, and 25 in variable yields and selectivities. The reactions take place either spontaneously or in the presence of MgI2 as a mild Lewis acid depending on the type of substrate. Release of the chiral
亲核共轭加成的手性甲醛Ñ,Ñ -dialkylhydrazones 1到双重激活环烯烃2 - 8个前进顺利,得到相应的迈克尔加成物14,16,18,20,22,24,和25中的可变产率和选择性。反应自发或在MgI 2存在下进行取决于底物的类型,为温和的路易斯酸。通过将moiety部分转化为缩醛,二硫缩醛或腈来实现手性助剂的释放。