Stannic Chloride–Iodine: An Efficient Reagent for Regioselective Synthesis of Furan–Fused Heterocycles
摘要:
SnCl4-I-2-mediated cyclization of ortho-cyclohexenyl phenol and ortho-cyclohexenyl enol derivatives of coumarin, uracil, dimedone, and pyrone at room temperature for 1 h give the linear cyclized products in 78-90% yield, which, on treatment with 10% Pd-C at 250 degrees C for 1-2 h, afford corresponding aromatized products in 80-84% yield.
Synthesis of Dimedone-Annelated Heterocycles: Regioselective Heterocyclization of 2-(Cyclohex-2′-enyl)-5,5-dimethyl-3-hydroxy cyclohex-2-enone
摘要:
2-(Cyclohex-2'-enyl)-5,5-dimethyl-3-hydroxycyclohex-2-enone undergoes regioselective heterocyclization to give bridged heterocycles 5a,b and 7 on treatment with pyridine hydrotribromide or hexamethylenetetramine hydrotribromide (I h); or elemental bromine (7 h); N-iodosuccinimide in acetonitrile at. 0-5degreesC (I h) and cone. H2SO4 at 0-5degreesC (2 h), respectively.