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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: ...
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.
Phenylboronic acid or benzeneboronic acid, abbreviated as PhB(OH) 2 where Ph is the phenyl group C 6 H 5 - and B(OH) 2 is a boronic acid containing a phenyl substituent and two hydroxyl groups attached to boron. Phenylboronic acid is a white powder and is commonly used in organic synthesis.
The boron atom of a boronic ester or acid is sp 2 hybridized possessing a vacant p orbital, enabling these groups to act as Lewis acids. The C–B bond of boronic acids and esters are slightly longer than typical C–C single bonds with a range of 1.55-1.59 Å.
This page contains tables of azeotrope data for various binary and ternary mixtures of solvents. The data include the composition of a mixture by weight (in binary azeotropes, when only one fraction is given, it is the fraction of the second component), the boiling point (b.p.) of a component, the boiling point of a mixture, and the specific gravity of the mixture.
The pinacol reaction is extremely well-studied and tolerates many different reductants, including electrochemical syntheses.Variants are known for homo- and cross-coupling, intra- and inter-molecular reactions with appropriate diastereo- or enantioselectivity; [2] as of 2006, the only unsettled frontier was enantioselective cross-coupling of aliphatic aldehydes. [3]
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 .
Basic heteroaromatic boronic acids (boronic acids that contain a basic nitrogen atom, such as 2-pyridine boronic acid) display additional protodeboronation mechanisms. [4] A key finding shows the speciation of basic heteroaromatic boronic acids to be analogous to that of simple amino acids , with zwitterionic species forming under neutral pH ...