Synthesis and Reactions of 1,3,5-Tri- and 1,3,5,7-Tetracarbonyl Compounds

The reaction of 1,3-bis(silyloxy)-1,3-butadienes with functionalized and nonfunctionalized acid chlorides and bis(acid chlorides) gives rise to the formation of a great variety of 1,3,5-tri- and 1,3,5,7-tetracarbonyl compounds and cyclic products derived from them. Examples include functionalized and nonfunctionalized 3,5-dioxopentanoates, 3,5-dioxopimelates, 3-alkylidene-3H-isobenzofuran-1-ones, salicylates, 3(2H)furanones, and 3-oxo-4-sulfonylesters. Methylation and cyclopropanation reactions of 1,3,5-tri- and 1,3,5,7-tetracarbonyl compounds do not provide access to the expected permethylated and cyclopropanated polycarbonyl compounds. However, the latter could be prepared by stepwise protocols. The reaction of 1,3,5-tri- and 1,3,5,7-tetracarbonyl compounds with dinucleophiles resulted in cyclization reactions to give a variety of heterocyclic structures.

1 Introduction

2 Reactions of 1,3-Bis(silyloxy)-1,3-butadienes with Acid Chlorides

3 Reactions of 1,3,5-Tri- and 1,3,5,7-Tetracarbonyl Compounds

4 Conclusion

Enantioselective Fluorination of α-Branched β-Ynone Esters Using a Cinchona-Based Phase-Transfer Catalyst

Herein, we report the fluorination of α-branched β-ynone esters to afford their corresponding quaternary fluorinated products with good enantioselectivity (ee = 73-90%) using a cinchona-based phase-transfer catalyst. α-Branched β-ynone esters possess a highly acidic α-proton and form their corresponding enolate as a single isomer, which allows the enantioselective fluorination reaction to occur under standard cinchona-based phase-transfer catalyst conditions. Moreover, the obtained α-fluorinated product can be treated with [(SPhos)AuNTf₂] (1 mol %) to afford a fluorinated 3,5-diketo carboxylic acid.