36650-62-1

Upstream product

• 3901-07-3 3-(4-methoxy-phenyl)acrylic acid methyl ester 
• 832-01-9 methyl p-methoxycinnamate 
• 98977-48-1 (E)-3-(4-methoxyphenyl)acrylic anhydride 
• 943-89-5 (E)-3-(4-methoxyphenyl)acrylic acid 
• 123-11-5 4-methoxy-benzaldehyde 
• 67-56-1 methanol 
• 21204-67-1 methyl (triphenylphosphoranylidene)acetate 
• 116108-67-9 3,4-bis(4-methoxyphenyl)cyclobutane-1,2-dicarboxylic acid 

Downstream Products

• 832-01-9 methyl p-methoxycinnamate 

Relevant academic research and scientific papers

Megastigmane, benzyl and phenethyl alcohol glycosides, and 4,4'- dimethoxy-β-truxinic acid catalpol diester from the leaves of Premna subscandens Merr.

Extensive isolation work on the n-BuOH-soluble fraction obtained from the leaves of Premna subscandens, collected on Ishigaki island, Okinawa, afforded six compounds. Two were identified as megastigmane glucosides, 7- (3,5-dihydroxy-1,1,5-trimethylcyclohexylidene)-9-methylprop-8-enyl 9-O-β-D- glucopyranoside and 3-hydroxy-5,6-epoxy-β-ionol 9-O-β-D-glucopyranoside. The structures of the remaining four new compounds were elucidated to be a 2'-O-β-D-apiofuranosyl derivative of 3-hydroxy-5,6-epoxy-β-ionol 9-O-β-D- glucopyranoside, named premnaionoside, benzyl alcohol β-D-(2'-O-β-D- xylopyranosyl)glucopyranoside, phenethyl alcohol β-D-(2'-O-β-D- glucopyranosyl)glucopyranoside, and 4,4'-dimethoxy-β-truxinic acid catalpol diester by spectroscopic analyses.

Photocatalytic Oxidative [2+2] Cycloelimination Reactions with Flavinium Salts: Mechanistic Study and Influence of the Catalyst Structure

Flavinium salts are frequently used in organocatalysis but their application in photoredox catalysis has not been systematically investigated to date. We synthesized a series of 5-ethyl-1,3-dimethylalloxazinium salts with different substituents in the positions 7 and 8 and investigated their application in light-dependent oxidative cycloelimination of cyclobutanes. Detailed mechanistic investigations with a coumarin dimer as a model substrate reveal that the reaction preferentially occurs via the triplet-born radical pair after electron transfer from the substrate to the triplet state of an alloxazinium salt. The very photostable 7,8-dimethoxy derivative is a superior catalyst with a sufficiently high oxidation power (E=2.26 V) allowing the conversion of various cyclobutanes (with Eox up to 2.05 V) in high yields. Even compounds such as all-trans dimethyl 3,4-bis(4-methoxyphenyl)cyclobutane-1,2-dicarboxylate can be converted, whose opening requires a high activation energy due to a missing pre-activation caused by bulky adjacent substituents in cis-position.

Construction of Cyclobutanes by Multicomponent Cascade Reactions in Homogeneous Solution through Visible-Light Catalysis

[2+2] Photocycloaddition of two olefins is a general method to assemble the core scaffold, cyclobutane, found in numerous bioactive molecules. A new approach to synthesize cyclobutanes through multicomponent cascade reactions by merging aldol reaction and Witting reaction with visible-light-induced [2+2] cycloaddition is reported. An array of cyclobutanes with high selectivity has been achieved from commercially available aldehydes, ketones (or phosphorus ylide), and olefins with visible-light irradiation of a catalytic amount of (fac-tris(2-phenylpyridinato-C2,N)iridium) ([Ir(ppy)3]) at room temperature. Control experiments and spectroscopic studies revealed that the triplet–triplet energy transfer from the excited [Ir(ppy)3]* to enones, generated in situ from aldehyde and ketone or aldehyde and phosphorus ylide, is responsible for these simple and efficient muticomponent transformations.

Photocatalytic Systems with Flavinium Salts: From Photolyase Models to Synthetic Tool for Cyclobutane Ring Opening

Two new photocatalytic systems based on flavinium species formed in situ by protonation of riboflavin-tetraacetate (1) with triflic acid or prepared in advance via alloxazine quaternization are presented as effective tools for oxidative cyclobutane ring [2 + 2] cycloreversion using visible light. The system with 1,3-dimethyl-8-trifluoromethylalloxazinium perchlorate (2c) was found to be superior allowing an acid-free mild procedure, which results in the opening of cyclobutanes with high oxidation potential (up to 2.14 V) and/or with sensitive groups (e.g., furan) without side reactions.

Templating photodimerization of trans-cinnamic acid esters with a water-soluble Pd nanocage

A water-soluble octahedral Pd nanocage acting as a reaction vessel templates the photodimerization of substituted trans-cinnamic acid methyl esters in water. Irradiation of the host-guest complexes of trans-cinnamic acid methyl esters with the Pd nanocage resulted in selective formation of a syn head-head dimer in addition to the corresponding cis isomer. These results suggest that the guest molecules are preoriented in a selective fashion with the hydrophilic ester group facing water and the hydrophobic aryl group tucked within the cavity of the host. Such an orientation occurs at the hydrophobic-hydrophilic interface between the nanocage exterior and interior. Weak intermolecular C-H-π and π-π interactions between the host and the guest(s) are likely to be responsible for the lack of mobility of the reactant olefins during their short excited-state lifetime.

Photochemical dimerization of methoxy substituted cinnamic acid methyl esters

Photochemical dimerization of methyl methoxycinnamates was studied. Dimer formation was observed both in unsensitized and in sensitized reactions. The reactions showed a high stereoselectivity.