87303-91-1

Upstream product

• 67-56-1 methanol 
• 51196-02-2 5,7,3',4'-tetra-O-methylepicatechin 
• 51079-25-5 (2R,3S)-(+)-catechin 3',4',5,7-tetramethyl ether 
• 186581-53-3 diazomethane 
• 480-17-1 (+)-leucocyanidin 

Downstream Products

• 25095-07-2 Acetic acid (2R,3S)-2-(3,4-dimethoxy-phenyl)-4,5,7-trimethoxy-chroman-3-yl ester 

Relevant academic research and scientific papers

Site-Selective Alkoxylation of Benzylic C?H Bonds by Photoredox Catalysis

Methods that enable the direct C?H alkoxylation of complex organic molecules are significantly underdeveloped, particularly in comparison to analogous strategies for C?N and C?C bond formation. In particular, almost all methods for the incorporation of alcohols by C?H oxidation require the use of the alcohol component as a solvent or co-solvent. This condition limits the practical scope of these reactions to simple, inexpensive alcohols. Reported here is a photocatalytic protocol for the functionalization of benzylic C?H bonds with a wide range of oxygen nucleophiles. This strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C?O bonds with high site selectivity, chemoselectivity, and functional-group tolerance using only two equivalents of the alcohol coupling partner. This method enables the late-stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential applications in synthesis and medicinal chemistry.

Regio- and stereoselective oxidation of flavan-3-ol-, 4-arylflavan-3-ol-, and biflavanoid derivatives with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)

The phenolic methyl esthers of flavan-3-ols, 4β-arylflavan-3-ols, and (-)-fisetinidol-(4β,8)-(+)-catechin biflavanoids are susceptible to regio- and stereoselective methoxylation at C-4 in moderate yields with DDQ in CHCl3-MeOH solution. The observed asymmetric induction with exclusive formation of 2,4-trans products is compatible with the intermediacy of a diastereogenic donor-acceptor interaction, DDQ acting as the acceptor and oxidant. The 4-funtionalized analogues are of both synthetic and degradative significance in condensed tannin chemistry.

STEREOSPECIFIC FUNCTIONALIZATION OF THE HETEROCYCLIC RING SYSTEMS OF FLAVAN-3-OL AND -BIFLAVAN-3-OL DERIVATIVES WITH 2,3-DICHLORO-5,6-DICYANO-1,4-BENZOQUINONE (DDQ)

Efficient stereospecific 4-methoxylation of both 2,3-trans- and 2,3-cis-flavan-3-ol methyl ethers with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in CHCL3-MeOH solution is of both synthetic and degradative significance in oligomeric flavanoid chemist

Synthesis of Condensed Tannins. Part 1. Stereoselective and Stereospecific Syntheses of Optically Pure 4-Arylflavan-3-ols, and Assessment of their Absolute Stereochemistry at C-4 by means of Circular Dichroism

Stereoselective and also stereospecific condensation at C-4 of flavan-3,4-diols of known absolute configuration with phloroglucinol and resorcinol in acid medium proceeds at ambient temperatures with partial retention of configuration for 2,3-trans-isomers and with inversion for 2,3-cis-analogues.Circular dichroism spectra of the resultant 4-arylflavan-3-ols all exhibit multiple Cotton effects.The sign of high intensity Cotton effects to low wavelength, contributed by aryl chromophores at C-4, may almost invariably be correlated with the absolute configuration at this chiral centre of 2,3-trans-3,4-trans, 2,3-trans-3,4-cis, and 2,3-cis-3,4-trans-isomers.