Studies on Pd(II)-Catalyzed Coupling−Cyclization of α- or β-Amino Allenes with Allylic Halides
摘要:
The palladium-catalyzed coupling-cyclization of alpha- or beta-amino allenes with allylic halides leading to 3-allylic 2,5-dihydropyrroles and 1,2,3,6-tetrahydropyridines, respectively, was studied. The starting materials are easily available. The skeletons of both two classes of products were established by the X-ray diffraction studies of 7i and 9b. Through the study of the reaction of 2b with 3-chloro-1-butene, 1-chloro-2-butene, and pi-allyl palladium species and the stereochemical outcome of the coupling cyclization of (S)-2m and (R)-2n, it is believed that the current transformation most likely proceeded via a Pd(II)-catalyzed pathway, although a Pd(0) pathway cannot be completely excluded.
Rhodium‐Catalyzed Dynamic Kinetic [4+2] Cycloaddition of Allene‐1,3‐Dienes
作者:Yulin Han、Anni Qin、Qian Zhang、Xue Zhang、Hui Qian、Shengming Ma
DOI:10.1002/anie.202211635
日期:2022.11.21
A rhodium/Malphos catalytic recipe has been developed for the dynamic kinetic intramolecular Diels–Aldercycloaddition of allene-1,3-dienes. The desired cis-fused [4.3.0]bicyclic products were obtained with decent yields and excellent stereo- and enantioselectivity. Its dynamic kinetic nature has been confirmed by careful mechanistic studies.