6-Di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) capped Pd(0) nanoparticles (TzPdNPs) as a catalyst in the Sonogashiracoupling of aryl halides in aqueous medium with diminished homocoupling is reported. The methodology provides a facile route to obtain polyfunctional alkynes under ligand- and copper-free conditions. The procedure is also efficient for aryl chlorides.
Azahomosteroid ringsystems were synthesized through two-component coupling of γ,δ-unsaturated Fischer carbene complexes with o-alkynylheteroaryl carbonyl derivatives. The reaction occurs through the formation of azaisobenzofuran as transient intermediate; the latter undergoes a subsequent Diels–Alder cycloaddition reaction with in-built dienophile with high regio- and stereoselectivity.
Annulation of furan-bridged 10-membered rings on N-heterocycles through [8+2] cycloaddition of dienylazaisobenzofurans and dimethyl acetylenedicarboxylate
作者:Priyabrata Roy、Binay K. Ghorai
DOI:10.1016/j.tetlet.2011.08.094
日期:2011.10
One-pot three-componentcoupling of o-alkynylheteroaryl carbonyl derivatives with α,β-unsaturated Fischer carbene complexes and dimethyl acetylenedicarboxylate leading to the synthesis of heterocyclic analogues of furanophane derivatives has been explored. This involves the generation of conformationally flexible dienylazaisobenzofuran intermediate as transient intermediates, which undergo [8+2] cycloaddition