1,5-二取代的 pent-1-en-4-yn-1-ones 与芳基肼在酸化酒精中的缩合主要导致相应的芳基腙的形成,在双键处有痕量的环化副产物 – 1,5 -二芳基-3-(芳基乙炔基)-4,5-二氢-1 H-pyrazoles (pyrazolines). Arylhydrazones are cyclized only by refluxing in high-boiling polar solvents (DMF and ethylene glycol), with the selective formation of 1,5-disubstituted 3-styrylpyrazoles in up to 77–95% yields. Thermodynamically, the cyclization of arylhydrazones at the triple bond is the
Asymmetric Synthesis of Less Accessible α-Tertiary Amines from Alkynyl <i>Z-</i>
Ketimines
作者:Taichi Kano、Yusuke Aota、Keiji Maruoka
DOI:10.1002/anie.201710084
日期:2017.12.18
highly stereoselective synthesis of hitherto less accessible chiral α‐tertiary amines with multiple structurally similar linear carbon chains was achieved through chiral auxiliary mediated addition of organolithium reagents to the geometrically well‐controlled alkynyl Z‐ketimines. This stereoselective nucleophilic addition offers a general approach to the asymmetric synthesis of nitrogen‐containing