Horner-wadsworth-emmons
Horner-wadsworth-emmons - Related Videos
12:21
Probing the Brain in Autism Using fMRI and Diffusion Tensor Imaging
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Cited by 15 •
2011
Neuroimaging techniques, such as functional MRI and Diffusion Tensor Imaging have become increasingly useful in characterizing the cognitive and neural deficits in autism. An examination of brain connectivity in autism at a network level along with adaptations for scanning children with developmental disabilities is presented.
06:56
Rabies Necropsy Techniques in Large and Small Animals
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Cited by 2 •
2019
The goal of this protocol is to demonstrate safe necropsy techniques in small and large animals to obtain satisfactory tissue samples for rabies testing.
07:54
Detection of Rabies IgG and IgM Antibodies Using the Rabies Indirect Fluorescent Antibody Test
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2024
The aim of this manuscript is to examine the use of the rabies indirect fluorescent antibody test for the detection of rabies-specific IgG and IgM antibodies.
12:07
Using an EEG-Based Brain-Computer Interface for Virtual Cursor Movement with BCI2000
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Cited by 26 •
2009
In this video, we demonstrate the steps required to run a brain-computer interface experiment, including setting up the EEG cap, calibrating the system, and training the user to move a cursor in two dimensions using imagined movements.
09:59
Respiratory Exam I: Inspection and Palpation
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2023
Source: Suneel Dhand, MD, Attending Physician, Internal Medicine, Beth Israel Deaconess Medical Center Disorders of the respiratory system with a chief complaint of shortness of breath are among the most common reasons for both outpatient and inpatient evaluation. The most obvious visible clue to a respiratory problem will be whether the patient is displaying any signs of respiratory distress, such as fast respiratory rate and/or cyanosis. In a clinical situation, this will always require...
FAQs
A base removes a proton from the phosphonate-stabilized carbon nucleophile, generating the reactive carbon species needed for carbon-carbon bond formation. That nucleophile then adds to an aldehyde or ketone, creating an intermediate that undergoes elimination. This sequence connects the phosphonate-derived carbon to the carbonyl carbon while producing a phosphate byproduct and establishing the alkene framework.
The reaction commonly gives E-alkenes, meaning the larger substituents lie on opposite sides of the double bond, but this preference is not universal. Substrate structure, phosphonate design, solvent, and base can all influence the observed stereoselectivity. Consequently, chemists consider both reagent structure and reaction conditions when planning an alkene-forming step.
Several controllable features affect the product ratio: the structure of the aldehyde or ketone, the design of the phosphonate, the selected base, and the solvent. These variables influence how the carbon nucleophile forms and how the elimination proceeds. Adjusting them can therefore change the balance between alkene geometries rather than merely changing reaction speed.
A typical sequence begins by combining a phosphonate-stabilized carbon nucleophile precursor with a suitable base. The activated nucleophile is then brought into reaction with an aldehyde or ketone, followed by elimination that forms the alkene and a phosphate byproduct. The substrate, phosphonate, base, and solvent must be considered together because they influence the final alkene selectivity.
The method is valuable when a synthesis requires a defined alkene unit to connect two molecular fragments. Its predictable carbon-carbon bond formation and potential for stereochemical control make it useful in constructing pharmaceuticals, natural products, and other complex molecules. Chemists can select aldehyde or ketone substrates and phosphonate partners to place the new alkene within a larger structure.
The isolated alkene reveals both whether the intended carbon-carbon connection formed and which alkene geometry was favored. An E-rich product can indicate that the chosen substrate, phosphonate, base, and solvent combination supported the common stereochemical preference, while a different ratio signals that those structural or reaction variables strongly affected selectivity.