117760-33-5

Upstream product

• 109-99-9 tetrahydrofuran 
• 3156-07-8 methyl phenyl ketene 
• 675825-21-5 Lithium enolate of the acetaldehyde 
• 221878-99-5 (S)-(+)-2-phenylpropionic acid vinyl ester 
• 108-05-4 vinyl acetate 
• 492-37-5 hydratropic acid 

Downstream Products

• 79121-13-4 (R)-2-phenylpropionic acid-(R)-1-phenylethyl ester 
• 221878-99-5 (S)-(+)-2-phenylpropionic acid vinyl ester 

Relevant academic research and scientific papers

Selective racemisation of esters: Relevance to enzymatic hydrolysis reactions

The selective racemisation of an ester in the presence of the corresponding acid has been demonstrated. Phenyl esters are significantly more prone to racemisation than methyl esters. Preliminary results indicate the utility of these results in enzyme-catalysed hydrolysis reactions.

Model Studies on the Enzyme-Regulated Stereodivergent Cascade Passerini Reaction

The synthesis of chiral α-acyloxy carboxamides containing two stereogenic centers continues to be a challenging field of organic chemistry. Herein, we have proposed and proved the feasibility of an enzyme regulated-cascade reaction, which using the same substrates enables the formation of individual stereoisomers of α-acyloxy carboxamides with up to 99 % ee. The access to the individual stereoisomeric products has been achieved by a combination of the enzymatic kinetic resolution of racemic vinyl esters, subsequent Passerini reaction, and enzymatic kinetic resolution of formed α-acyloxy carboxamides. The presented studies are promising in exploratory proof-of-concept of enzyme-controlled stereodivergent cascade to form an important class of chiral compounds for medicinal chemistry.

Dual Activity of Grubbs-Type Catalyst in the Transvinylation of Carboxylic Acids and Ring-Closing Metathesis Reactions

The development of a multifunctional catalyst, which mimics the promiscuity of enzymes, that would catalyze more than one chemical transformation in a single reaction vessel is one of the key points of modern sustainable chemistry. The results of our experiments indicated that Grubbs-type catalysts possess such multitask activity, catalyzing the transvinylation reaction of carboxylic acids without losing their original metathetic activity. This new activity of Grubbs catalysts was evidenced on several examples. It allows us to design a transvinylation/ring-closing metathesis (RCM) cascade reaction leading to the formation of endocyclic enol lactones from unsaturated carboxylic acids in an one-pot procedure. This unique ability of Grubbs catalyst to catalyze multiple mechanically distinct cascade reactions in a chemoselective way offers the new possibility for the synthesis of complex compounds from simple, easily accessible substrates.

Au(I) complexes-catalyzed transfer vinylation of alcohols and carboxylic acids

Au(I) complexes-catalyzed transfer vinylation of alcohols and carboxylic acids has been achieved. The catalyst system consists of 2 mol % AuClPPh3 and 2 mol % AgOAc. Primary alcohols and secondary alcohols were converted into corresponding vinyl ethers in good yield (64-93%); however, tertiary alcohols showed poor reactivities. Carboxylic acids were also transformed into corresponding vinyl esters in good yield (78-96%).

Improvement of enantioselectivity in kinetic resolution of a primary alcohol through lipase-catalyzed transesterification by using a chiral acyl donor

The enantioselectivity of the kinetic resolution of a primary alcohol which has a chiral center at the β-position of the hydroxyl group was substantially improved by employing a racemic mixture of a chiral acyl donor for enantioselective transesterification catalyzed by a lipase. The combination of the lipase, solvent, and acyl donor was also effective for the enantioselectivity. In addition, the important effect of the chirality of an acyl donor on kinetic resolution was investigated by using enantiomerically pure acyl donors. Here we demonstrate the effective kinetic resolution (E=98) of a primary alcohol, 2-phenyl-1-propanol, by using a racemic mixture of a chiral acyl donor, vinyl 3-phenylbutanoate. Copyright (C) 2000 Elsevier Science Ltd.

Nucleophilic Additions to Ketenes by (Trimethylsilyl)lithium and by Enolates

Reaction of t-Bu2C=C=O (5) with Me3SiLi at -78 deg C followed by trapping of the intermediate enolate with Ac2O gave t-Bu2C=C(OAc)SiMe3 (9).Other ketenes gave similar products.Reaction of ketenes PhCR=C=O (R = Me, 13; R = Et, 3) with enolates CH2=C(OLi)R1 (R1 = H, Me, t-Bu, Ph) at -78 deg C followed by warming to 25 deg C and hydrolysis gave vinyl esters PhCHRCO2C(R1)=CH2, along with 10 percent PhCHMeCOCH2COPh for R = Me, R1 = Ph.Under the same conditions the ketenes PhCR=C=O with enolates CH2=C(OK)R1 (R1 = Me, t-Bu, Ph) gave only 1,3-diketones PhCHRCOCH2COR1, but vinyl esters were the major products if the reactions were quenched at -78 deg C.It is proposed that enolates undergo preferential O-acylation by ketenes in a kinetically favored process, but that these intermediates can revert to thermodynamically more stable C-acylated products.

OXYGEN AND CARBON-ACYLATION OF ENOLATES BY KETENES

Ketenes react with lithium enolates mainly by O-acylation, thus providing a convenient route to vinyl esters and their enolates.