21504-23-4

Upstream product

• 4638-79-3 2-chloro-2-phenylacetaldehyde 
• 67-56-1 methanol 
• 14371-19-8 cis-β-methoxystyrene 
• 4110-75-2 (E)-(2-methoxyvinyl)benzene 
• 122-78-1 phenylacetaldehyde 
• 2612-41-1 α,α-(dibromomethyl)phenylmethanol 
• 14371-25-6 2-bromo-1,1-dimethoxy-2-phenylethane 
• 59950-99-1 α-chlorophenylacetaldehyde dimethyl acetal 
• 21087-52-5 trans-2-methoxy-3-phenyloxirane 

Downstream Products

• 34025-29-1 mandelaldehyde 
• 108-93-0 cyclohexanol 

Relevant academic research and scientific papers

Selective oxidation of vinyl ethers and silyl enol ethers with hydrogen peroxide catalyzed by peroxotungstophosphate

The oxidation of vinyl and silyl enol ethers with aqueous hydrogen peroxide was first achieved by the use of peroxotungstophosphate (PCWP) as the catalyst. For example, the oxidation of 1-ethoxy-1-octene with a stoichiometric amount of 35% H2O2 in the presence of PCWP (0.5 mol %) in a mixed solvent of methanol and dichloromethane at room temperature gave 1- ethoxy-1-methoxy-2-hydroxyoctane, a synthetic equivalent of 2- hydroxyoctanal, in 70% yield. The oxidation of acyclic silyl enol ethers such as 1-[(trimethylsilyl)oxy]-1-octene under these conditions gave 1-hydroxy-2- octanone in 725 yield, while the same oxidation in dichloromethane alone resulted in cleavage of the enol double bond to form heptanal in 71% yield. Cyclic silyl enol ethers were converted into the corresponding α-hydroxy ketones in 48-71% yields under similar reaction conditions.

Enantiomerically pure α-methoxyaryl acetaldehydes as versatile precursors: a facile chemo-enzymatic methodology for their preparation

A facile and efficient synthesis of optically active α-methoxyaryl acetic acids (up to 95% ee), α-methoxyaryl ethanols (up to 93% ee) and α-methoxyaryl acetonitriles (up to 93% ee) was achieved via Arthrobacter sp. lipase-catalyzed kinetic resolution of masked aldehydes as the key synthons, that is, α-hydroxyaryl acetaldehyde acetals.

α-Hydroxylation of carbonyls using iodine

The α-hydroxylation of ketones and aldehydes to α-hydroxyketals mediated by iodine under basic conditions in MeOH is described. Enolates generated under the reaction conditions are iodinated and the resulting α-iodocarbonyl is transformed into the hydroxyketal. The use of iodine for this chemistry represents an economical and practical alternative to existing methods for this transformation.

An efficient procedure to α-hydroxyaldehyde dimethyl acetals

α-Hydroxyaldehyde dimethyl acetals are prepared efficiently by conversion of α-haloaldehyde dimethyl acetals into α-haloaldehyde hemiacetal acetates and subsequent methanolysis promoted by lithium methoxide.

ELABORATION OF THE ACYL LIGAND IN (η5-C5H5)Fe(CO)(PPh3)(COCH2OCH3)

Deprotonation of the complex (η5C5H5)Fe(CO)(PPh3)(COCH2OCH3) leads to anion 7 which can be alkylated stereoselectively to products of RFeRα/SFeSα configuration.Reaction of 7 with acetaldehyde or benzaldehyde are not stereoselective and yield four stereoisomeric products 16-19 or 20-23, respectively.Exchange of the lithium cation for diethylaluminium or divalent tin cations improves the stereoselectivity in reaction of 7 with carbonyl compounds.Reaction of 7 with acetone leads to product 24 of the RFeSα/SFeRα configuration.Decomplexation of 20with NBS and methanol is connected with decarbonylation and leads to mandelaldehyde dimethyl acetal.With other alcohols mixtures of diastereoisomeric mixed acetals are formed.Similar results are achieved with other mild oxidizing reagents as cerium ammonium nitrate or selenium dioxide.Oxidation of 20 with m-chloroperoxybenzoic acid leads mainly to one of the diastereoisomeric acetals although in a low yield.Decomplexation of 15 with NBS and ethanol leads to mixed acetal 29.

Oxygenation of Aromatic Vinyl Ethers. A Noticeable Formation of Epoxides and Reaction Mechanism

cis-β-Alkoxystyrenes such as cis-β-methoxy-, cis-β-ethoxy-, and cis-β-isopropoxystyrene were autoxidized as neat at room temperature in the dark even in the absence of any radical generator.UV-irradiation and the use of a radical generator facilitated the oxygenation of these olefins.These oxidations afforded the corresponding epoxides or their derivatives in considerable yields as well as carbonyl compounds resulting from oxidative cleavage of the double bonds.The mechanisms for these oxidations are proposed to involve free-radical chain pathways and charge-transfer complexes between the olefins and oxygen play an important role in the initiation steps.