Double intramolecular hetero Diels–Alder reactions of α,β-unsaturated hydrazones as 1-azadienes: a new route to 2,2′-bipyridines
作者:Nicholas Bushby、Christopher J. Moody、David A. Riddick、Ian R. Waldron
DOI:10.1039/b105409k
日期:——
Salicylaldehyde was converted into the O-propynyl- and O-butynyl α,β-unsaturated aldehydes 4 and ketones 6, subsequent reaction of which with N,N-dimethylhydrazine and alkyne homocoupling gave the 1,3-diyne bis(hydrazones) 8, substrates for a double intramolecular hetero Diels–Alder reaction. Similar substrates 11, 15a/15c and 15b/15d were prepared from 2-(N-benzoylamino)cinnamaldehyde, hex-5-ynol and hept-6-ynol
水杨醛被转化为不饱和的O-丙炔基和O-丁炔基醛类 4和酮类 6,其后的反应与N,N-二甲基肼 和 炔烃均相偶合得到1,3-二炔双(hydr)8,是双分子内杂Diels-Alder反应的底物。类似的基材11,15A / 15C和15B / 15D,从制备2-(N-苯甲酰氨基)肉桂醛, 己-5-炔醇 和 庚-6-炔诺醇分别。加热1,3-二炔基双(α,β-不饱和腙)8a,8c,11和15a导致分子内Diels-Alder双反应,在失去芳香化后产生二甲胺,2,2'-联吡啶21–24。