Catalytic Use of Zinc Amide for Transmetalation with Allylboronates: General and Efficient Catalytic Allylation of Carbonyl Compounds, Imines, and Hydrazones
The efficient catalytic allylation of ketones, imines, and hydrazones with allylboronates using a catalytic amount of zinc amide is reported. In this reaction, the boron‐to‐zinc exchange process occurred smoothly to afford the corresponding allylzinc amides, and the desired allylation reactions proceeded in high efficiency (∼0.1 mol%). A mechanistic study revealed that transmetalation was a rate‐determining
Asymmetric addition of allyltrimethylsilane to (–)-menthyl pyruvate and phenylglyoxylate
作者:Iwao Ojima、Yuji Miyazawa、Miyoko Kumagai
DOI:10.1039/c39760000927
日期:——
The reaction of allyltrimethylsilane with α-keto esters in the presence of titanium tetrachloride afforded a γδ-unsaturated α-hydroxyvalerate in high yield, which with chiral α-keto esters in asymmetric synthesis gave 16–55% enantiomeric excess product.
Allylation reactions of carbonyl compounds such as aldehydes and reactive ketones using allyltrimethoxysilane in aqueous media proceeded smoothly in the presence of 5 mol% of a CdF2-terpyridine complex; the presence of the ligand plays an important role for the catalytic activity; the catalyst was easily recovered and reused without loss of activity.