Highly effective tandem hydroformylation–acetalization of olefins using a long-life Brønsted acid–Rh bifunctional catalyst in ionic liquid–alcohol systems
作者:Xin Jin、Kun Zhao、Feifei Cui、Fangfang Kong、Qiangqiang Liu
DOI:10.1039/c3gc41231h
日期:——
A robust and highly effective tandem hydroformylationâacetalization of olefins using a Brønsted acidâRh bifunctional catalyst (ARBC) in ionic liquidâalcohol systems is reported. The key feature of the ARBC is its use of a zwitterionic phosphine ligand bearing an amino acid tag. This novel ARBC shows an excellent catalytic efficiency and a long service life without a significant drop in both the hydroformylation efficiency and the acetalization efficiency or Rh loss for more than seventeen cycles. We believe that the long-term high activity and acetal selectivity mainly benefit from the synergy between the acidic active site and the Rh active site on the ARBC and the highly effective immobilization and recycling of ARBC in ionic liquidâalcohol systems due to the strong affinity of ARBC for the ionic liquid.
Hydroformylation of terminal alkenes in alcohol solvents leads to the selective formation of the corresponding acetals. The Xantphos ligand gave the best results as well as acetal selectivities higher than 99% and linear/branched ratios of up to 52 were obtained. The scope of the reaction was studied. Acetals were found to be unreactive under hydroaminomethylation conditions.
Phosphonium-based aminophosphines as bifunctional ligands for sequential catalysis of one-pot hydroformylation–acetalization of olefins
作者:Peng Wang、Huan Liu、Yong-Qi Li、Xiao-Li Zhao、Yong Lu、Ye Liu
DOI:10.1039/c5cy01827g
日期:——
involved bifunctional moieties of the phosphine fragment and Lewis acidic phosphonium were linked together by stable chemical bonds and bridged by one N-atom. The molecular structure of the L2-ligated Rh-complex (Rh-L2) indicated that such bifunctionalities were well retained without incompatibility problems. Investigations on co-catalysis over L1–L3 showed that L3 exhibited the best sequential catalysis
The present invention relates to: a novel dienal compound which has an aromatic odor useful for use as a compound flavor raw material or the like; and a flavor composition containing the dienal compound. The dienal compound according to the present invention is characterized by being represented by general formula (1):
(wherein R represents an alkyl group having 8 to 10 carbon atoms; and a wavy line represents a cis form, a trans form, or a mixture of a cis form and a trans form).
Monothioacetals are obtained by treating the corresponding acetals with organotin thiophenoxides in the presence of BF2·OEt2. The reaction proceeds under mild conditions to provide the desired compounds with high selectivity.