Indium-Mediated Allylation of Carbonyl Compounds in Ionic Liquids: Effect of Salts in Ionic Liquids

• Main Authors: Tsunehisa Hirashita, Fusako Takahashi, Takayuki Noda, Yuji Takagi, Shuki Araki
• Format: Article
• Language: English
• Published: MDPI AG 2018-07-01
• Series: Molecules
• Subjects: indium; allylation; ionic liquids; carbonyl compounds; homoallylic alcohols
• Online Access: http://www.mdpi.com/1420-3049/23/7/1696

The In-mediated allylation of carbonyl compounds can be performed in various types of solvents including ionic liquids. However, we have found that in [bmim][BF4] (where bmim = 1-butyl-3-methylimidazolium), the In-mediated coupling of crotyl bromide with benzaldehyde gives a complex mixture, and some additives, such as halides and amines, are crucial for the successful conversion to the corresponding γ-adduct. Instead, the addition of alcohols or water promotes the formation of the α-adduct. An asymmetric induction with up to 62% enantiomeric excess (ee) was observed employing cinchonidine as an additive in a binary solvent consisting of an ionic liquid and dichloromethane.