37749-86-3

Upstream product

• 6581-66-4 2-methoxytetrahydropyran 
• 670-80-4 4-cyclohexen-1-ylmorpholine 
• 2761-33-3 2-acetoxytetrahydropyran 
• 6651-36-1 1-(Trimethylsilyloxy)cyclohexene 
• 3136-02-5 2-chlorotetrahydro-2H-pyran 

Downstream Products

• 55277-27-5 Acetic acid 5-[2-oxo-cyclohex-(E)-ylidene]-pentyl ester 
• 16121-27-0 Acetic acid 5-(2-oxo-cyclohexyl)-pentyl ester 

Relevant academic research and scientific papers

Chemoselective aldol type condensation of silyl enol ethers and acetals in 5 mol dm-3 lithium perchlorate-diethyl ether

Acetals are efficiently and chemoselectively converted into the corresponding aldol ethers upon treatment with 1-trimethylsilyloxycyclohexene 2 in 5 mol dm-3 lithium perchlorate-diethyl ether (LPDE) at ambient temperature with moderate diastereoselectivity, whereas under the same conditions aldehydes and ketals fail to react with 2.The present method allows the acetal substitution to be carried out under neutral reaction and work up conditions.A mechanism involving the formation of an oxocarbenium ion intermediate from the acetal followed by nucleophilic addition of the silyl enol ether is proposed.The observed chemoselectivity is attributed to the mild Lewis acidity of the lithium ion in diethyl ether.

Reaction of Enamines with Acetals or Trialkyl Orthoformates Activated by Lewis Acids

Enamines, prepared readily from various carbonyl compounds, react with acetals or trialkyl orthoformates in the presence of Lewis acids such as BF3.OEt2 to give corresponding β-alkoxy carbonyl compounds or α-dialkoxymethyl carbonyl compounds in good yields.The reaction of dienamines with acetals or trialkyl orthoformates also selectively gives corresponding β,χ-unsaturated α-(α-alkoxyalkyl) carbonyl compounds or β,χ-unsatureted α-dialkoxymethyl carbonyl compounds in good yields.

Lewis Acid-mediated α-Alkoxyalkylation of Carbonyl Compounds Using α-Halo and α-Acetoxy Ethers. - Synthesis of C-Glycosides

α-Chloro and α-acetoxy ethers such as 2a-b or 4a-b react with silyl enol ethers, O-silylketene acetals, and bis-silylated acyloins in the presence of ZnX2 to form α-alkoxylalkylated carbonyl compounds.The ambident alkylating agent 36 reacts regioselectively at the oxygen-substituted C-atom to afford products such as 39, 41, and 43.The method is mild, regiospecific with respect to isomeric silyl enol ethers and does not afford undesired polyalkylated products.It can be applied in the synthesis of C-glycosides such as 52, 54, and 55.

REACTIONS OF α-HETEROATOM-SUBSTITUTED ETHERS AND SULFIDES WITH SILYL ENOL ETHERS. CHEMOSELECTIVITY IN THE CLEAVAGE OF HETEROATOM-CARBON BONDS BY IODOTRIMETHYLSILANE AND TRIMETHYLSILYL TRIFLUOROMETHANESULFONATE

Reactions of α-heteroatom substituted ethers and related compounds (R1R2CXY; X, Y = RO, RS and Cl) with silyl enol ethers and ketene silyl acetals took place in the presence of iodotrimethylsilane (Ia) and trimethylsilyl triflate (Ib) as a catalyst and factors influencing the activation of the heteroatom by I were examined.