Synthesis Of Cyclic Compounds From ?,?-Unsaturated Ketones Compounds

This thesis is consists of two parts:in part one,an efficient method for the synthesis of double functionalized furan derivatives that are dificult to access by other methods was developed.This process was realized by iodocyclization of alkynylated enaminone;Part two is base-promoted synthesis of functionalized medium-sized ring or fused-ring compounds from the reactions of ynones and unstrained cyclic ?-dicarbonyl compounds.In part one,I2-mediated approach to the synthesis of highly substituted 3-formyl-4-iodo furans through intramolecular nucleophilic addition of alkynylated enaminone has been developed.The cyclization reactions are believed to proceed through activation of the carbon-carbon triple bond by coordination to I2,and then subsequent intramolecular attack of the carbonyl oxygen gives the corresponding iminium cation.Subsequent hydrolysis to give 3-formyl-4-iodo furan derivatives.Fourteen compounds were synthesized in 45-90%yields.In part two,we have developed an efficient base-promoted ring-expansion reaction of unstrained cyclic ?-dicarbonyl compounds using ynones as the reaction partner.This methodology represents a transition-metal-free insertion reaction of isolated internal alkynes into carbon-carbon 8-bonds of unstrained cyclic ?-dicarbonyl compounds for the synthesis of functionalized medium-sized ring compounds.Twelve compounds were synthesized in 40-78%yields and one of which was characterized by X-ray single crystal diflfraction;When ynones bearing an ortho-halide-substituted arene ring on the carbonyl carbon was used as start material,it could undergo further intramolecular nucleophilic aromatic substitution(SNAr)to give medium-sized fused-ring compounds at 80 ?.Fifteen compounds were synthesized in 48-86%yields and one of which was characterized by X-ray single crystal diffraction.All new compounds in this paper were characterized by 1H NMR?13C NMR and HRMS spectroscopy.