51985-11-6

Upstream product

• 204690-29-9 1-m-hydroxyphenyl-1-phenyl-1-ethanol 
• 108-86-1 bromobenzene 
• 121-71-1 3-Hydroxyacetophenone 
• 3262-89-3 triphenylboroxine 
• 98-80-6 phenylboronic acid 
• 100-58-3 phenylmagnesium bromide 

Downstream Products

• 204690-29-9 1-m-hydroxyphenyl-1-phenyl-1-ethanol 
• 775331-14-1 2-hydroxy-4-(1-phenylvinyl)benzaldehyde 

Relevant academic research and scientific papers

Direct Observation of Photoinduced Ultrafast Generation of Singlet and Triplet Quinone Methides in Aqueous Solutions and Insight into the Roles of Acidic and Basic Sites in Quinone Methide Formation

Femtosecond time-resolved transient absorption spectroscopy experiments and density functional theory computations were done for a mechanistic investigation of 3-(1-phenylvinyl)phenol (1) and 3-hydroxybenzophenone (2) in selected solvents. Both compounds went through an intersystem crossing (ISC) to form the triplet excited states T? and Tn? in acetonitrile but behave differently in neutral aqueous solutions, in which a triplet excited state proton transfer (ESPT) induced by the ISC process is also proposed for 2 but a singlet ESPT without ISC is proposed for 1, leading to the production of the triplet quinone methide (QM) and the singlet excited QM species respectively in these two systems. The triplet QM then underwent an ISC process to form an unstable ground state intermediate which soon returned to its starting material 2. However, the singlet excited state QM went through an internal conversion process to the ground state QM followed by the formation of its final product in an irreversible manner. These differences are thought to be derived from the slow vinyl C-C rotation and the moderate basicity of the vinyl C atom in 1 as compared with the fast C-O rotation and the greater basicity of the carbonyl O atom of 2 after photoexcitation. This can account for the experimental results in the literature that the aromatic vinyl compounds undergo efficient singlet excited state photochemical reactions while the aromatic carbonyl compounds prefer triplet photochemical reactions under aqueous conditions. These results have fundamental and significant implications for understanding of the ESPT reactivity in general, as well as for the design of molecules for efficient QM formation in aqueous media with potential applications in cancer phototherapy.

Nickel-Catalyzed Direct Synthesis of Aryl Olefins from Ketones and Organoboron Reagents under Neutral Conditions

Nickel-catalyzed addition of arylboron reagents to ketones results in aryl olefins directly. The neutral condition allows acidic protons of alcohols, phenols, and malonates to be present, and fragile structures are also tolerated.

Nonlinear solvent water effects in the excited-state (formal) intramolecular proton transfer (ESIPT) in m-hydroxy-1,1-diaryl alkenes: Efficient formation of m-quinone methides

The photohydration of hydroxy-substituted 1,1-diaryl alkenes 1-3 has been studied in aqueous CH3CN solution. Evidence for formation of quinone methide intermediates was provided by product studies and by observation of its absorption spectrum by laser flash photolysis. For the meta isomers, the proposed mechanism of m-quinone methide formation probably involves a solvent-mediated ("proton-relay") excited-state (formal) intramolecular proton transfer (ESIPT) from the phenol hydroxyl group to the β-carbon of the alkene moiety in neutral aqueous CH3CN solution, either in a concerted manner or via two very fast steps. The m-quinone methides are then trapped by water to form the corresponding diaryl ethanol product with high overall quantum yield. Evidence for the ESIPT pathway was provided by fluorescence and LFP measurements. The addition of small amounts of water (3CN) decreased the fluorescence emissions of 1 and 2 with a concomitant increase in production of m-quinone methides. Stem-Volmer analyses of fluorescence data revealed a dynamic and a minor static quenching component, both of which involved a water trimer cluster. The degree of charge transfer from the phenol (phenolate) oxygen to the alkene β-carbon, which may be thought of as the driving force for this efficient ESIPT, is pronounced for the meta isomer in the excited state, consistent with Zimmerman's "meta-ortho effect". Alkenes 1 and 2 were shown to be more efficient in m-quinone methide photogeneration than the hydroxy-substituted benzyl alcohol 8, which required conditions of higher water content for similar quantum yields.