6552-78-9

Upstream product

• 14371-10-9 (E)-3-phenylpropenal 
• 104-55-2 3-phenyl-propenal 
• 17592-47-1 meso-1,6-diphenyl-hexa-1,5-diyne-3,4-diol 
• 6738-06-3 phenylethynylmagnesium bromide 
• 2579-22-8 Phenylpropargyl aldehyde 

Downstream Products

• 19308-98-6 trans-4,5-Diphenyl-cyclopenten-⁽¹⁾-yl-aldehyd 

Relevant academic research and scientific papers

Selective Pinacol-Coupling Reaction using a Continuous Flow System

The first continuous flow pinacol coupling reaction of carbonyl compounds was successfully achieved within only 2 min during a single pass through a cartridge filled with zinc(0). The optimized method allowed the efficient production of gram-scale value-added compounds with high productivity. The developed methodology is efficient for aromatic or α,β-unsaturated aldehydes but gives moderate results for more stable acetophenone derivatives. Moreover, the flow method displayed better results in terms of yield and selectivity in comparison to the corresponding batch methodology.

First pinacol coupling in emulsified water: Key role of surfactant and impact of alternative activation technologies

For the first time, the influence of surfactants on the radical pinacol coupling reaction is investigated. The rate and selectivity of this reductive C-C coupling are compared under three different activation technologies: thermal activation, microwave irradiation, and sonication. The use of IgepalCO520, a neutral surfactant, led to the successful conversion of aromatic or α,β-unsaturated aliphatic carbonyl compounds in moderate to excellent yield (55-90 %). An insight on the potential mechanism involved in the reaction is also proposed, based on microscopic observations and particle size measurement.

Selective Pinacol Coupling on Regeneratable Supported Acids in Sole Water

Efficient pinacol coupling was developed in sole water, using a reusable heterogeneous supported acid source and zinc as cheap available metal source. This medium can be easily regenerated up to 10-fold without loss of activity. Moreover, supported acids enhance the selectivity of the pinacol coupling reaction compared with homogeneous acids.

A new Yb3+-catalyzed pinacol and imine-coupling reaction

Ytterbium triflate, Yb(OTf)3, catalyzes the intermolecular reductive homocouplings of imines, aldehydes, and ketones at loadings of 5 mol % in the presence of Mg and Me3SiCl to give isolated yields of up to 95%. Diastereoselectivity of up to 4/96 (dl/meso) is achieved for aromatic aldehydes, up to 100% dl for aliphatic aldehydes, and 100% dl for an intramolecular imine coupling.

The electrosynthesis of pinacols

Electrosynthesis of pinacols by iron as electrode in acid condition is performed. The influence of electric potential and time on pinacol yield is explored. The optimal reaction conditions are at electric potential 4 V, time 60 min., methanol (6 mL), hydrochloric acid (2 N, 2 mL), with the yield of pinacols up to 18-81%. The main advantages of the present procedure are milder reaction conditions and operational simplicity.

The pinacol coupling of aromatic aldehydes in ethyl acetate mediated by TiCl4-Al

Titanium tetrachloride in ethyl acetate can be reduced by Al powder to the corresponding low valent titanium complexes, which can mediate the conversion of some aromatic aldehydes into the corresponding pinacols in 23-93% yields within 25-120 min under stirring at r.t. When N,N,N′,N′- tetramethylethylene diamine (TMEDA) is added, the diastereoselectivities of the reactions are improved.

Pinacol coupling of aromatic aldehydes and ketones in ethyl acetate mediated by TiCl4-Mg

Titanium tetrachloride in ethyl acetate can be reduced by Mg powder to the corresponding low-valent titanium complexes, which can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 38-85% yields within 15-60 min at rt with stirring. Copyright Taylor & Francis Group, LLC.

Studies on the lanthanum-induced pinacol coupling of aromatic aldehydes and ketones in aqueous media

The pinacol coupling of aromatic aldehydes and ketones was carried out in 16-71% yield using La-36%HAc-CH2Cl2 system with stirring at rt in 4 h. The reactions in the same system gave pinacols in 12-91% yield under ultrasound irradiation at rt in 2 h. Copyright Taylor & Francis Group, LLC.

Pinacol coupling of aromatic aldehydes and ketones using TiCl 3-Al-EtOH under ultrasound irradiation

Titanium trichloride in EtOH can be reduced by Al to the corresponding low-valent titanium complexes. This can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 40-82% yields within 30-90 min at r.t. under ultrasound irradiation.

Pinacol coupling reaction of beta-halo-alpha,beta-unsaturated aldehydes promoted by TiI4.

The pinacol reaction of beta-halogenated alpha,beta-unsaturated aldehydes was promoted by titanium tetraiodide to give coupling products in good yields with high dl-selectivity. Subsequent reduction with H(2)/Pd-C gave saturated vic-diols in good yields. Heck coupling reaction enabled the displacement of halogens with vinyl groups without the loss of stereochemical integrities. [reaction: see text]