Disubstituted Boranes
Disubstituted Boranes - Related Videos
02:37
Disubstituted Cyclohexanes: cis-trans Isomerism
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2023
Depending upon the different spatial orientation of the substituents, the disubstituted cycloalkanes exhibit two types of stereoisomers. The cis isomers have the substituents on the same side of the ring, whereas the trans isomers have the substituents on the opposite sides. These stereoisomers exhibit different physical properties and cannot be interconverted without breaking the carbon-carbon bonds. In cyclohexane, the substituents can occupy different positions generating distinct isomers.
01:18
Directing and Steric Effects in Disubstituted Benzene Derivatives
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2023
When disubstituted benzenes undergo electrophilic substitution, the product distribution depends on the directing effect of both substituents. When the directing effects of both substituents reinforce each other, a single product is obtained. For example, bromination of p-nitrotoluene occurs ortho to the methyl group and meta to the nitro group, which is the same position, resulting in a single product. However, if the directing effects of the two groups oppose each other, the more strongly...
09:00
Lewis Acid-Base Interaction in Ph3P-BH3
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2023
Source: Tamara M. Powers, Department of Chemistry, Texas A&M University One of the goals of chemistry is to use models that account for trends and provide insights into the properties of reactants that contribute to reactivity. Substances have been classified as acids and bases since the time of the ancient Greeks, but the definition of acids and bases has been modified and expanded over the years.1 The ancient Greeks would characterize substances by taste, and defined acids as those that...
08:19
Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles
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Cited by 3 •
2016
The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.
10:49
Nanomoulding of Functional Materials, a Versatile Complementary Pattern Replication Method to Nanoimprinting
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Cited by 1 •
2013
We describe a nanomoulding technique which allows low-cost nanoscale patterning of functional materials, materials stacks and full devices. Nanomoulding can be performed on any nanoimprinting setup and can be applied to a wide range of materials and deposition processes.
FAQs
The empty p orbital at boron makes these molecules Lewis acidic, so they can accept electron density from donor molecules and interact readily with unsaturated bonds. This electronic feature explains why disubstituted boranes participate in hydroboration and form useful organoboron intermediates rather than behaving as electronically saturated three-coordinate compounds.
Hydroboration converts the B–H bond and an unsaturated bond into two new connections in a single concerted process. One product bond links boron to carbon, while the hydrogen forms a C–H bond at the other carbon. The reaction therefore transforms an alkene or alkyne into an organoboron-containing intermediate.
A concerted pathway means that C–B and C–H bond formation occurs together as the unsaturated substrate reacts with the B–H bond. This directly connects the starting unsaturation to the organoboron product and avoids describing the transformation as a sequence of independently formed ionic intermediates, clarifying the reaction’s fundamental bonding pattern.
Their distinctive feature is that the boron atom already carries two organic substituents before hydroboration occurs. When the B–H bond adds across an alkene or alkyne, those substituents remain attached to boron in the resulting organoboron intermediate. This preserves preselected organic groups for subsequent synthetic transformations.
A typical conceptual workflow begins by exposing the disubstituted borane to an alkene or alkyne. Hydroboration then forms C–B and C–H bonds through the concerted addition of the B–H bond. The resulting organoboron intermediate can subsequently serve as a route to alcohols, amines, or other functionalized molecules.
These intermediates extend the value of hydroboration beyond simple bond addition. They provide entry points to alcohols, amines, and other functionalized molecules, making the reaction useful for constructing more elaborated organic products. In this way, the boron-containing intermediate acts as a platform for further synthetic development.