NMR and Stereochemistry Concepts

Flashcards based on NMR techniques, stereochemistry, and reactions involving alkynes.

NMR (Nuclear Magnetic Resonance)

A technique that uses magnetic fields and radio waves to determine the structure of organic compounds.

Splitting

The phenomenon in NMR where the signal of a proton is split into multiple peaks due to neighboring protons.

Shielding

The process in NMR that occurs when electrons shield the nucleus from the external magnetic field, affecting the resonance frequency.

Integration

The area under the peaks in an NMR spectrum, which correlates to the number of protons representing the ratio of different types of protons.

Equivalent protons

Protons in a molecule that are in identical environments and therefore resonate at the same frequency in NMR.

Chiral molecules

Molecules that are not superimposable on their mirror images, having at least one chiral center.

Achiral molecules

Molecules that can be superimposed on their mirror images and do not have chiral centers.

Stereocenter

A point in a molecule at which the interchange of two groups produces a stereoisomer.

Isomers

Compounds with the same molecular formula but different structural arrangements.

Stereoisomers

Isomers that have the same connectivity but differ in the spatial arrangement of their atoms.

Constitutional isomers

Isomers that have the same molecular formula but differ in the connectivity of their atoms.

Cis/trans isomers

Types of stereoisomers where groups are attached to the same or adjacent carbon atoms but differ in spatial arrangement.

Enantiomers

A pair of stereoisomers that are non-superimposable mirror images of each other.

Diastereomers

Stereoisomers that are not mirror images of each other and have different physical properties.

Naming R vs S stereocenters

CIP priority rules are used to assign the configuration of chiral centers as R (rectus) or S (sinister) based on the spatial arrangement of groups.

Nomenclature in Alkynes

The systematic naming of alkyne compounds, which contain carbon-carbon triple bonds.

Alkyne + HX reactions

Reactions involving alkynes and hydrogen halides, which can occur in both 1 eq and 2 eq, following specific mechanisms.

Alkyne + X2 reactions

Reactions involving alkynes and halogens, which occur with reactions only and require specific stoichiometry.

Alkyne + H2 Lindlar vs. Pt/C vs. Na/NH3

Different methods to hydrogenate alkynes, which yield different products under various conditions.

Alkyne + H2O with acid reactions

Hydration reactions of alkynes in the presence of acids leading to the formation of ketones or aldehydes.

Alkyne + H2O with Boron reagent

Reactions involving alkynes and boron reagents that proceed via anti-Markovnikov addition.

Alkyne + NaNH2 and alkyl halide

A type of reaction involving alkynes that forms new carbon-carbon bonds via nucleophilic substitution.