Osmium-Catalyzed 7-endo Heterocyclization of Aromatic Alkynols into Benzoxepines
作者:Alejandro Varela-Fernández、Cristina García-Yebra、Jesús A. Varela、Miguel A. Esteruelas、Carlos Saá
DOI:10.1002/anie.201000455
日期:——
The wizard of Os: Regioselective osmium‐catalyzed 7‐endo heterocyclization of aromaticalkynols affords benzoxepines in good yields. The proposed catalytic cycle involves the key formation of osmium–vinylidene complexes via an alkynyl‐hydride–osmium(IV) complex from the starting alkynol.
Experimental and Computational Study of an Unexpected Iron-Catalyzed Carboetherification by Cooperative Metal and Ligand Substrate Interaction and Proton Shuttling
作者:Osama El-Sepelgy、Aleksandra Brzozowska、Luis Miguel Azofra、Yoon Kyung Jang、Luigi Cavallo、Magnus Rueping
DOI:10.1002/anie.201708240
日期:2017.11.20
An iron‐catalyzedcycloisomerization of allenols to deoxygenated pyranose glycals has been developed. Combinedexperimental and computationalstudies show that the iron complex exhibits a dual catalytic role in that the non‐innocent cyclopentadienone ligand acts as proton shuttle by initial hydrogen abstraction from the alcohol and by facilitating protonation and deprotonation events in the isomerization