Synthetic Strategies

Parashar, Rakesh Kumar

doi:10.1002/9781118681299.ch1

Cited by 1 publication

(1 citation statement)

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“…The control of selectivity is very important for organic synthesis, especially for those catalyzed by transition metal complexes, as they can often catalyze more than one chemical reaction from the same starting materials . To enhance the selectivity of metal catalysts, the most common way is to tune the steric and electronic properties of metal complexes through ligand modification .…”

Section: Introductionmentioning

confidence: 99%

Selectivity Enhancement in Dynamic Kinetic Resolution of Secondary Alcohols through Adjusting the Micro-Environment of Metal Complex Confined in Nanochannels: A Promising Strategy for Tandem Reactions

et al. 2014

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Dichloro(η 6 -p-cymene) (1-butyl-3-cyclohexylimidazolin-2-ylidene) ruthenium(II) (RuL) was synthesized and confirmed. Five heterogeneous catalysts with similar ruthenium cores were prepared by chemical immobilization method using various silica-based supports, including mesoporous silica SBA-15 of different pore sizes (Ru/Si-9, Ru/Si-8, and Ru/Si-7), nonporous silica particles (Ru/SiO 2 ), and surface trimethylsilylated SBA-15 (Ru/SiMe). The dynamic kinetic resolution (DKR) of 1-phenylethanol, which includes metal−enzyme bicatalytic racemization in tandem with stereoselective acylation, gave product in 99% yield and 0% ee with homogeneous catalyst RuL, whereas the heterogeneous Ru/Si-8 exhibited high catalytic activity and enantioselectivity (up to 96% yield and 99% ee). The racemization and acylation abilities of different catalysts were analyzed. The influences of pore size and surface properties for heterogeneous catalysts were investigated, and the nanocage effect was found to be the key factor in stereoselectivity. The catalyst Ru/Si-8 performed well in reactions with various substrates and can be reused for at least seven times.

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Section: Introductionmentioning

confidence: 99%