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It has the formula [(CH 3) 4 C 2 O 2 B] 2; the pinacol groups are sometimes abbreviated as "pin", so the structure is sometimes represented as B 2 pin 2. It is a colourless solid that is soluble in organic solvents. It is a commercially available reagent for making pinacol boronic esters for organic synthesis.
Examples of boronic esters Boronic ester Diol Structural formula Molar mass CAS number Boiling point (°C) Allylboronic acid pinacol ester: pinacol: 168.04: 72824-04-5: 50–53 (5 mmHg) Phenyl boronic acid trimethylene glycol ester: trimethylene glycol: 161.99: 4406-77-3: 106 (2 mm Hg) Diisopropoxymethylborane: isopropanol: 144.02 86595-27-9: ...
Pinacol is a branched alcohol which finds use in organic syntheses. It is a diol that has hydroxyl groups on vicinal carbon atoms. A white solid that melts just above room temperature, pinacol is notable for undergoing the pinacol rearrangement in the presence of acid and for being the namesake of the pinacol coupling reaction .
The Miyaura borylation has shown to work for: Alkyl halides, [2] aryl halides, [1] [3] [4] aryl halides using tetrahydroxydiboron, [5] aryl halides using bis-boronic acid, [6] aryl triflates, [7] aryl mesylates, [8] vinyl halides, [9] vinyl halides of α,β-unsaturated carbonyl compounds, [10] and vinyl triflates.
Compounds of the type BR n (OR) 3-n are called borinic esters (n = 2), boronic esters (n = 1), and borates (n = 0). Boronic acids are key to the Suzuki reaction. Trimethyl borate, debatably not an organoboron compound, is an intermediate in sodium borohydride production.
1,2-Dichlorobenzene or ortho-dichlorobenzene; 1,3-Dichlorobenzene or meta-dichlorobenzene; 1,4-Dichlorobenzene or para-dichlorobenzene. All three isomers are colorless chlorobenzenes with the formula C 6 H 4 Cl 2. They differ structurally based on where the two chlorine atoms are attached to the ring.
The reaction is named after pinacol (also known as 2,3-dimethyl-2,3-butanediol or tetramethylethylene glycol), which is the product of this reaction when done with acetone as reagent. The reaction is usually a homocoupling but intramolecular cross-coupling reactions are also possible. Pinacol was discovered by Wilhelm Rudolph Fittig in 1859.
MIDA boronate esters and organotrifluoroborates have both been utilised in "slow release" strategies, in which the reaction conditions are optimised to provide a slow release of boronic acid. This protocol has proved useful in the cross-coupling of some notoriously unstable boronic acids, such as the 2-pyridine boronic acid.