Gold–Catalyzed Oxidation/Dearomatization Reaction Of Ynone To Construct The Natural Product Skeleton Of Spiro [4,5] Nonanetrione

Spiro[4.5]decanone is important motif in natural products and biologically active molecules,which plays an important role in nature,medicine and biology areas.In this thesis,phenol as nucleophile participates the oxidation/dearomatization reaction of ynone,and the mechanism of gold-catalyzed S_N2’type nucleophilic reaction was briefly introduced.In this thesis,the topic focus on gold–catalyzed oxidation/dearomatization reaction of ynone to construct the natural product skeleton of spiro[4,5]nonanetrione via the Carbon-4of phenol as a nucleophilic to work with alkyne.The high-efficiency construction of the natural product skeleton of the spiro[4,5]decanetrione was achieved,and some research results were obtained.The main research contents are as follows:1.The phenol substituted ynone derivatives were synthesized by using the simple p-hydroxybenzaldehyde as the starting material via TBS protected the hydroxyl group,Grignard reaction and oxidation reaction and etc.2.The natural product skeleton of spiro[4,5]nonanetrione was successfully constructed under the gold catalytic system.When the end of ynones were installed by an aliphatic group,the optimum reaction conditions was:KAu Cl₂·2H₂O（10 mol%）;2,6-dichloropyridinium oxynitride（2 equivalents）as the oxidant,DCM as the solvent,room temperature.Five aliphatic functional groups substituted substrates were extended under the optimal reaction conditions,and good yield of corresponding products were obtained.When the end of ynones were installed by an aryl group,the optimum reaction conditions was:X-Phos Au Cl（10 mol%）/Ag NTf₂（10 mol%）;6-dichloropyridinium oxynitride（2 equivalents）is the oxidant,DCM is used as the reaction solvent;room temperature.Nine aryl substituted substrates were extended under the optimal reaction conditions,and good yield of corresponding products were obtained（up to 76%yield）3.In this thesis,preliminary antifungal activity screening was performed on all the new spiro[4,5]nonanetrione.Five of the compounds（3-2a,3-4a,3-7a,3-9a,3-10a）howed visible antibacterial activity.