57279-03-5

Upstream product

• 186581-53-3 diazomethane 
• 137304-11-1 2-(tert-Butyl-dimethyl-silanyl)-4-methyl-furan-3-carboxylic acid 
• 101870-15-9 4-methyl-3-furancarboxylic acid 
• 133620-36-7 2-(tert-Butyl-dimethyl-silanyl)-furan-3-carboxylic acid 
• 29379-19-9 3-methoxycarbonyl γ-crotonolactone 
• 54467-56-0 6a-methoxycarbonyl-3a,4,6,6a-tetrahydrofuro[3,4-c]pyrazole-4(1H)-one 
• 54467-57-1 4-methyl-3-methoxycarbonyl-2,5-dihydrofuran-5-one 
• 617-52-7 Dimethyl itakonate 
• 99523-16-7 dimethyl 2-bromo-2-(bromomethyl)succinate 

Downstream Products

• 101870-15-9 4-methyl-3-furancarboxylic acid 

Relevant academic research and scientific papers

Synthesis of neo-tanshinlactone Via the palladium-mediated intramolecular biaryl coupling reaction

Neo-tanshinlactone (1) was synthesized by the intramolecular aryl-aryl coupling reaction of the precursor ester, which was prepared from the corresponding furan carboxylic acid (13) and naphthol (3), using a palladium reagent.

Regioselective Preparation of 2,4-, 3,4-, and 2,3,4-Substituted Furan Rings. 2. Regioselective Lithiation of 2-Silylated-3-substituted Furan Rings

A new method for the preparation of 3,4- and 2,5-disubstituted furan rings is described. A variety of 2-silylated-3-(hydroxymethyl)furans and 2-silylated-3-furoic acids lithiate exclusively at C-4 when treated with 2.2 equivs of BuLi. The resulting dianions were quenched with a variety of electrophiles to provide 2-silylated-3-(hydroxymethyl)-4-substituted furans and 2-silylated-4-substituted 3-furoic acids in good to excellent yields. Removal of the silyl group (n-Bu4NF) provided a variety of 4-substituted-3-(hydroxymethyl)furans and methyl 4-substituted-3-furoates, respectively. The latter esters were prepared due to difficulties encountered in isolating 4-substituted-3-furoic acids. The site of lithiation was altered by protecting the 3-hydroxyl group with a triethylsilane. Lithiation of 2-silylated-3-(((triethylsilyl)oxy)methyl)furan with 1.2 equivs of BuLi followed by the addition of electrophiles provided 2-silylated-3-(((triethylsilyl)oxy)methyl)-5-substituted furan rings. Subsequent removal of both silyl groups provided 2,4-disubstituted furan rings in moderate to good yields. A rationale is provided to explain why protection of the hydroxyl group at C-3 leads to a change in lithiation from the C-4 to the C-5 position of the furan ring. In addition, an explanation for the observed effect of adding HMPA or LiCl to the solution during the lithiation of 2-(tert-butyldimethylsilyl)-3-(hydroxymethyl)furan is provided.

The Regiospecific C-4 Lithiation of 2-(tert-Butyldimethylsilyl)-3-furoic Acid

2-(tert-Butyldimethylsilyl)-3-furoic acid 7 was regiospecifically lithiated at the C-4 position when treated with 2.5 equiv. of butyllithium (at -20 deg C) in either tetrahydrofuran or 1,2-dimethoxyethane; trapping of the dianion with a variety of electrophiles provided 2,3,4-trisubstituted furans in good to excellent yield.