Synthesis Of 3-iodo-1H-indene Derivatives And 2-pyridone Via Zirconium

A convenient BF₃·Et₂O-catalyzed Friedel-Crafts cyclization of iodinated allylic alcohols to multi-substituted indene derivatives is reported.The present reaction provides an efficient protocol to 3-iodo-1H-indene derivatives in good to high yields under mild conditions.Further,the iodoindene derivatives are valuable synthetic building blocks for elaboration of molecular complexity,such as in the construction of multiaryl substituted indenes by Suzuki coupling reaction.9 designed 3-iodo-1H-indene derivatives were synthesized with the yields from 55%to 90%.2 of the products were employed to Suzuki coupling reaction and the products were obtained in 65%and 68%yields,respectively.All compounds were characterized by ¹H and ¹³C NMR spectroscopy.One of the structure was confirmed by single X-ray diffraction.Selective preparation of 2-pyridones derivatives from two different alkynes and an isocyanate was achieved by a novel procedure in which an alkyne and an isocyanate couple first to give an azazirconacyclopentene followed by reaction with the propargyl bromide in the presence of 0.1 equiv of CuCl.This procedure gives only single products of 2-pyridones derivatives with excellent selectivity.4 products were synthesized with moderate yields.