27247-02-5

Upstream product

• 4693-91-8 4-methoxyphenyl-acetic chloride 
• 90-02-8 salicylaldehyde 
• 23000-33-1 3-(4-methoxyphenyl)coumarin 

Downstream Products

• 1404301-84-3 (S)-3-(4-methoxyphenyl)spiro[chroman-2,2'-[1,3]dithiane] 
• 1404301-66-1 2-(2-(1,3-dithian-2-ylidene)-2-(4-methoxyphenyl)ethyl)phenol 

Relevant academic research and scientific papers

Pd-Catalyzed Decarboxylative Asymmetric Protonation of Sterically Hindered α-Aryl Lactones and Dihydrocoumarins

Pd-catalyzed decarboxylative asymmetric protonation (DAP) has been developed for sterically hindered α-aryl lactone and dihydrocoumarin substrates. Optimization studies were conducted using δ-lactone- and dihydrocoumarin-derived α-aryl, β-oxo-allyl esters with 2,4,6-trimethoxyphenyl as the aryl substituent. In the absence of a chiral P,N-ligand, (1R,2S)-(?)ephedrine, a cheap and readily available chiral proton donor, induced enantioselectivities of up to 92% ee and 88% ee with lactone and dihydrocoumarin substrates, respectively. Bulky aryl groups containing di-ortho substitutions and naphthyl groups gave the highest enantioselectivities of up to 92% and 86%, respectively. A stereochemical rationale is proposed to explain the preferred sense of asymmetric induction. (Figure presented.).

Deracemization of α-aryl hydrocoumarins via catalytic asymmetric protonation of ketene dithioacetals

An unprecedented catalytic asymmetric protonation of ketene dithioacetals is described. Various racemic α-aryl hydrocoumarin derivatives are transformed into enantioenriched dithioacetal-protected hydrocoumarins in the presence of a chiral Br?nsted acid catalyst. A newly developed phosphoric acid, featuring the 3,5-bis(pentafluorothio)phenyl (3,5-(SF5) 2C6H3) substituent, is introduced. The obtained products can be easily converted into either hydrocoumarins or the corresponding chromans via simple hydrolysis or hydrogenation, respectively.