Chemoselective aldol condensation in 5 mol dm−3 lithium perchlorate–nitromethane. A comparison with lithium perchlorate–diethyl ether medium
作者:R. Sudha、S. Sankararaman
DOI:10.1039/a900095j
日期:——
Aldol reactions of silyl enol ethers with aldehydes proceed in 5 mol dm–3 lithium perchlorate–nitromethane medium at ambient temperature. The reaction is highly chemoselective such that only aldehydes and cyclic ketones reacted while acyclic and aromatic ketones failed to react. The same reaction is not promoted in 5 mol dm–3 lithiumperchlorate–diethylether medium. The difference between these two
The present invention relates to a process for producing 2-alkylcycloalkanones with a high yield and a high purity. In addition, the present invention also relates to a process for producing lactones as a useful perfume material for cosmetics, flavors, etc. More specifically, the present invention relates to a process for producing a 2-alkylcycloalkanone represented by the following general formula (2) which includes the step of subjecting a 2-(1-hydroxyalkyl)-cycloalkanone to dehydration and hydrogenation reaction in a flow of a hydrogen gas under a pressure of from 20 to 200 kPa (absolute pressure) in the presence of an acid and a platinum group metal catalyst; and a process for producing a lactone which includes the step of subjecting the 2-alkylcycloalkanone to oxidation reaction using a percarboxylic acid:
wherein n is an integer of 1 or 2; and R1 and R2 are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms with the proviso that R1 and R2 may form a ring through a carbon atom adjacent thereto.