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
Gold(I)-catalysed synthesis of cyclic sulfamidates: current scope, stereochemistry and competing ene-allene cycloisomerisation
作者:Mari C.M. Higginbotham、Lorna Kennedy、Anita G. Lindsay、Andreas Troester、Magnus W.P. Bebbington
DOI:10.1016/j.tet.2014.11.058
日期:2015.1
Six-membered cyclic sulfamidates are prepared in high yields by treatment of allenic sulfamates with readily available Ph3PAuNTf2. The reaction enables formation of N-substituted quaternary centres in high yields. The relative stereochemistry has been unambiguously determined. A π-rearrangement is faster than hydroamination in the case of an allyl-substituted sulfamate and a mechanism is proposed for
Game, set, and match: The first regio‐ and enantioselective version of the title reaction is described. The chiral catalyst prepared in situ from CrCl3 and a non‐C2‐symmetric bis(oxazoline) ligand 1 affords the valuable chiral β‐allenols regioselectively in good yields with excellent ee values. R=aryl, alkyl.