A novel sequential Pd-catalysed termolecular allenylation cascade/Ru catalysed RCM process affords a diverse range of Δ3-aryl/heteroaryl substituted five–seven membered nitrogen and oxygen heterocycles. Furtherelaboration, via 1,3-dipolar cycloaddition, in selected cases, afforded fused heterocyclic ring systems.
A novel sequential palladium/ruthenium-catalysed three-component process is described involving allenylation of aryl/heteroaryl iodides to generate (pi -allyl) palladium species which are intercepted by nitrogen nucleophiles to afford 1,6- and 1,7-dienes. Subsequent ring-closing metathesis affords N-heterocycles in good yield. (C) 2001 Elsevier Science Ltd. All rights reserved.
A ring closing metathesis-manganese dioxide oxidation sequence for the synthesis of substituted pyrroles
作者:Aaron Keeley、Shane McCauley、Paul Evans
DOI:10.1016/j.tet.2016.03.088
日期:2016.5
The combination of ring closing, or enyne metathesis with oxidation in order to prepare N-sulfonyl pyrroles is described. Reasonable to good yields were obtained for a variety of substituents and the procedure may also be conducted in one-pot. 2-Bromo N-sulfonyl adducts prepared in this manner were subjected to an intramolecular Heck-type cyclisation, forming cyclic sulfonamides.