Mechanism study on asymmetric Michael addition reaction between alkynone and α-angelica lactone catalyzed by chiral N, N'-dioxide-Sc(III) complex

Zuo, Yini; Meng, Xiangxiang; Hu, Changwei; Li, Jing; Su, Zhishan

doi:10.1016/j.cattod.2019.03.056

Cited by 3 publications

(2 citation statements)

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“…Although a versatile reactivity of α-angelica lactone has already been demonstrated in the synthesis of various alkyl levulinates, 60 cellulose esters, 61 γ-butyrolactones, 62,63 α-aminoγ-ketopimelates, 64 chiral γ-alkenyl butenolides, 65,66 as well as 2-amino-4-(2-furanone)-4H-chromene-3-carbonitriles, 67,68 only scare data concerning enzyme-catalyzed reactions can be found in the literature. 69−71 Moreover, to our best knowledge, none of the reports focused on the α-angelica lactone as "neutral-washable" acyl donor used in the separation of enantiomers from a bio-resolution.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Although a versatile reactivity of α-angelica lactone has already been demonstrated in the synthesis of various alkyl levulinates, cellulose esters, γ-butyrolactones, , α-amino-γ-ketopimelates, chiral γ-alkenyl butenolides, , as well as 2-amino-4-(2-furanone)-4 H -chromene-3-carbonitriles, , only scare data concerning enzyme-catalyzed reactions can be found in the literature. − Moreover, to our best knowledge, none of the reports focused on the α-angelica lactone as “neutral-washable” acyl donor used in the separation of enantiomers from a bio-resolution. Notably, our strategy was to employ α-angelica lactone, and not the levulinic acid ( LA ) or its aliphatic esters LAE , since the existing enol functionality among α - AL ’s inner structure should guarantee irreversibility of the reaction as the resultant enolate (enol-isomer) rapidly tautomerizes in situ into a more stable methyl ketone (keto-isomer), which is unable to react in the opposite direction, thus shifting the reaction’s equilibrium toward product formation (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

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From Waste to Value—Direct Utilization of α-Angelica Lactone as a Nonconventional Irreversible Acylating Agent in a Chromatography-Free Lipase-Catalyzed KR Approach toward sec-Alcohols

Poterała

Borowiecki

2021

ACS Sustainable Chem. Eng.

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Although the classical enzymatic kinetic resolutions (EKRs) are among the most important reactions in biocatalysis, the requirement of application of chromatographic purification technique, which is responsible for the generation of large amounts of waste organic solvents, is its major drawback. To minimize the environmental impact of such attempts and to address the current sustainability challenges, we decided to develop a novel EKR methodology, which relies on the usage of cheap, fully renewable, nontoxic, and irreversible acyl group donor reagent, namely, α-angelica lactone. The employed activated enol lactone-based acyl donor proved to be a versatile reagent enabling efficient and highly enantioselective (up to E ≫ 500) lipase-catalyzed resolution of a set of racemic sec-alcohols with up to >99% ee and near to quantitative isolation yields according to conversions achieved during the respective EKR procedure. Moreover, α-angelica lactone provided, in this case, an ability of fast and straightforward separation of the enzymatic reactions’ products via chromatography-free reactive liquid–liquid extraction (LLE) workup using either saturated aqueous sodium bisulfate in dimethylformamide (DMF) or Girard’s P reagent in a mixture of EtOH/AcOH (90:10, v/v), respectively. The NaHSO3/DMF LLE workup and the subsequent reisolation of the respective levulinate from the aqueous layer turned out to be less efficient than a separation with Girard’s P reagent. The selective LLE of optically active levulinate-Girard P-hydrazones from the respective alcohols and further hydrolysis of the respective hydrazides with diluted HClaq. could be performed with high levels of recovery of both EKR products isolated usually without loss of enantiomeric purity.

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